Hybrid nanoparticle TFC membranes

ABSTRACT

Reverse osmosis membranes made by interfacial polymerization of a monomer in a nonpolar (e.g. organic) phase together with a monomer in a polar (e.g. aqueous) phase on a porous support membrane. Interfacial polymerization process is disclosed for preparing a highly permeable RO membrane, comprising: contacting on a porous support membrane, a) a first solution containing 1,3-diaminobenzene, and b) a second solution containing trimesoyl chloride, wherein at least one of solutions a) and b) contains nanoparticles when said solutions are first contacted, and recovering a highly permeable RO membrane.

CROSS-REFERENCE TO RELATED U.S. APPLICATIONS

This application claims benefit of U.S. Provisional Applications:

-   -   61/045,262, filed Apr. 15, 2008;    -   61/045,234, filed Apr. 15, 2008;    -   61/045,237, filed Apr. 15, 2008;    -   61/045,247, filed Apr. 15, 2008;    -   61/045,249, filed Apr. 15, 2008;    -   61/045,252, filed Apr. 15, 2008;    -   61/079,794, filed Jul. 10, 2008    -   61/088,666, filed Aug. 13, 2008;    -   61/104,905, filed Oct. 13, 2008    -   61/122,341, filed Dec. 12, 2008;    -   61/112,342, filed Dec. 12, 2008;    -   61/122,343, filed Dec. 12, 2008;    -   61/122,344, filed Dec. 12, 2008;    -   61/122,345, filed Dec. 12, 2008;    -   61/122,346, filed Dec. 12, 2008;    -   61/122,347, filed Dec. 12, 2008;    -   61/122,348, filed Dec. 12, 2008;    -   61/122,350, filed Dec. 12, 2008;    -   61/122,351, filed Dec. 12, 2008;    -   61/122,352, filed Dec. 12, 2008;    -   61/122,354, filed Dec. 12, 2008;    -   61/122,355, filed Dec. 12, 2008;    -   61/122,357, filed Dec. 13, 2008;    -   61/122,358, filed Dec. 13, 2008;    -   61/156,388, filed Feb. 27, 2009;    -   61/156,394, filed Feb. 27, 2009; and    -   61/164,031, filed Mar. 27, 2009, all of which are incorporated        by reference, in their entireties.

FIELD OF THE INVENTION

This invention is related to thin film composite or TFC membranesincluding nanoparticles and/or other additives, and more particularly tosuch membranes used for reverse or forward osmosis, for example topurify water.

BACKGROUND OF THE INVENTION

Reverse osmosis membranes, made by interfacial polymerization of amonomer in a nonpolar (e.g. organic) phase together with a monomer in apolar (e.g. aqueous) phase on a porous support membrane are known as TFCmembranes and are used where flux and substantial rejectioncharacteristics are required, for example in the purification of water.Various materials have been added to TFC membranes to increase fluxwithout reducing rejection characteristics and have met with limitedsuccess. Such membranes are also subject to fouling resulting in reducedflux as contaminants, for example from the brackish or seawater to bepurified, build up on the surface of the discrimination layer of the TFCmembrane.

What are needed are techniques for further improving flux whilemaintaining or improving rejection characteristics, resisting theeffects of fouling, as well as techniques for improving commercialprocessing of such improved TFC membranes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating the layers in a step in theprocess of preparing a TFC membrane in which nanoparticles 16 arepresent in aqueous phase 14.

FIG. 2 is a block diagram illustrating the layers in a step in theprocess of preparing a TFC membrane in which nanoparticles 16 arepresent in organic phase 18.

FIG. 3 is a block diagram illustrating the layers in a step in theprocess of preparing a TFC membrane in which nanoparticles 16 arepresent in both aqueous phase 14 and organic phase 18.

FIG. 4 is a block diagram illustrating the layers in a step in theprocess of preparing a TFC membrane in which nanoparticles 16 arepresent in water solution 15 between porous support membrane 12 andaqueous phase 14.

FIG. 5 is a block diagram showing the use of a TFC membrane, havingnanoparticles 16 in a layer discrimination layer 24, in a reverseosmosis process.

FIG. 6 is a block diagram showing the use of a TFC membrane, havingnanoparticles 16 between discrimination layer 24 and porous supportmembrane 12, in a reverse osmosis process.

FIG. 7 is a TEM micrograph of discrimination layer 24 illustratingnanoparticles 16 in a thin film polymer matrix.

FIG. 8 is a cross section view of RO membrane 10 including nanoparticles16 in discrimination layer 24 on support membrane 24.

FIG. 9 is a cross section view of RO membrane 10 including nanoparticles16 in discrimination layer 24 on support membrane 24.

FIG. 10 is a diagrammatic view of RO membrane 10 during fabricationprocessing including soluble metal ions in aqueous phase 14.

FIG. 11 is a diagrammatic view of RO membrane 10 during fabricationprocessing including soluble metal ions in organic phase 18.

FIG. 12 is a diagrammatic view of RO membrane 10, includingnanoparticles and soluble metal ions 16 in discrimination layer 24during reverse osmosis.

FIG. 13 is a diagrammatic view of RO membrane 10 during fabricationprocessing including nanoparticles and soluble metal ions 16 in aqueousphase 14.

FIG. 14 is a diagrammatic view of RO membrane 10, includingnanoparticles and soluble metal ions 16 in discrimination layer 24during reverse osmosis.

FIG. 15 is a diagrammatic view of RO membrane 10 during fabricationprocessing including soluble metal ions 17 in aqueous phase 14 releasedin whole or in part from nanoparticles 16 in porous support membrane 12,or from other carriers.

FIG. 16 is a diagrammatic view of support membrane 12 during fabricationin which casting solution 13 is coated on fabric 20 on glass plate 15.

FIG. 17 is a diagrammatic view of RO membrane 10, including solublemetal ions 19 and/or soluble metal ions effect 19, in discriminationlayer 24 during reverse osmosis.

FIG. 18 is the chemical structure of mono-hydrolyzed TMC

FIG. 19 is a diagrammatic view of RO membrane 10 during fabricationprocessing including mono-hydrolyzed TMC 16 in organic phase 18.

FIG. 20 is a diagrammatic view of RO membrane 10, includingmono-hydrolyzed TMC 16 in discrimination layer 24 during reverseosmosis.

FIG. 21 is a 1H-NMR of mono-hydrolyzed TMC.

FIG. 22 is a diagrammatic view of RO membrane 10 during fabricationprocessing including molecular additive 16 in organic phase 18.

FIG. 23 is a diagrammatic view of RO membrane 10, including molecularadditive 16 in discrimination layer 24 during reverse osmosis.

FIG. 24 is a diagrammatic view of RO membrane 10 used to purifysaltwater.

FIG. 25 is a simple graphical representation of the reduced loss of fluxover time as a result of fouling for three different membraneconfigurations.

FIG. 26 is a graph relating membrane performance to purity ofmono-hydrolyzed TMC.

SUMMARY OF THE INVENTION

In one aspect, improved techniques for the use of nanoparticles in TFCmembranes have been developed including the combined used ofnanoparticles and/or nanotubes with alkaline earth metals,monohydrolyzed TMC and/or other molecular additives in hybridnanocomposite TFC membranes with increased flux, rejection andanti-fouling characteristics.

In another aspect, the new hybrid nanocomposite TFC membranes, togetherwith more advantages concentrations and ranges of TMC, MPD to TMC ratiosas well as the discovery of deflection points in the concentrations ofadditives, such as monohydrolyzed TMC, make the design and fabricationof engineered nanocomposite TFC membranes with selected flux, rejectionand antifouling characteristics possible.

In a further aspect, some of the new additives, particularly thealkaline earth metals and monohydrolyzed TMC, may be used for the designand fabrication of high flux, rejection and anti-fouling TFC membranes.These membranes may also advantageously use the advantageousconcentrations and ranges of TMC, MPD to TMC ratios and deflectionpoints in the concentrations of additives to provide optimumcharacteristics for particular circumstances.

One object of the invention is to provide an interfacial polymerizationprocess for preparing a highly permeable RO membrane, comprising:

-   -   contacting on a porous support membrane,        -   a) a first solution containing 1,3-diaminobenzene, and        -   b) a second solution containing trimesoyl chloride,    -   wherein at least one of solutions a) and b) contains well        dispersed nanoparticles when said solutions are first contacted,        and    -   recovering a highly permeable RO membrane.

A highly permeable reverse osmosis membrane produced by a process,comprising:

-   -   contacting on a porous support membrane,        -   a) a first solution containing 1,3-diaminobenzene, and        -   b) a second solution containing trimesoyl chloride,    -   wherein at least one of solutions a) and b) contains well        dispersed nanoparticles when said solutions are first contacted,        and    -   recovering a highly permeable RO membrane,    -   wherein at least 20% of the membrane surface area consists of        nanoparticles.        -   a) a first solution containing polyamine monomer, and        -   b) a second solution containing a polyfunctional acyl halide            monomer, a    -   wherein a molecular additive compound is present in a) or b) or        both during the polymerization reaction, and    -   recovering a highly permeable RO membrane.    -   Another object is to provide a highly permeable reverse osmosis        membrane, produced by an interfacial polymerization process,        comprising:    -   contacting on a porous support membrane,        -   a) a first solution containing a polyamine monomer and        -   b) a second solution containing a polyfunctional acyl halide            monomer,    -   wherein a molecular additive compound is present in a) or b) or        both during the polymerization reaction, and    -   recovering a highly permeable RO membrane.    -   Another object of the invention is to provide an interfacial        polymerization process for preparing a low-fouling highly        permeable RO membrane, comprising:    -   contacting on a porous support membrane,        -   a) a first solution containing a polyamine monomer, and        -   b) a second solution containing a polyfunctional acyl halide            monomer,    -   wherein aluminum ion is present in a) or b), or both, during the        polymerization reaction,    -   recovering a low-fouling, highly permeable RO membrane.    -   Another object is to provide a low-fouling highly permeable RO        membrane, produced by an interfacial polymerization process,        comprising:    -   contacting on a porous support membrane,        -   a) a first solution containing a polyamine monomer, and        -   b) a second solution containing a polyfunctional acyl halide            monomer,        -   wherein aluminum ion is present in a) or b), or both, during            the polymerization reaction.    -   Another object of the invention is to provide an interfacial        polymerization process for preparing a highly permeable RO        membrane, comprising:    -   contacting on a porous support membrane,        -   a) an aqueous solution containing metaphenylenediamine            (MPD), and        -   b) an organic solution containing trimesoyl chloride (TMC)            and a hydrolyzed TMC species, and    -   recovering a highly permeable RO membrane.    -   Another object is to provide a highly permeable reverse osmosis        membrane, produced by an interfacial polymerization process,        comprising:    -   contacting on a porous support membrane,        -   a) an aqueous solution containing metaphenylene diamine            (MPD), and        -   b) an organic solution containing trimesoyl chloride (TMC)            and a hydrolyzed TMC species, and    -   recovering a highly permeable RO membrane.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For clarity, the present disclosure is divided into multiple sections,as follows:

-   Section A: Improved Nanoparticles for enhanced TFC membrane    performance, including:    -   nanoparticle dispersion and sizing,    -   processing to enhance nanoparticle performance in a membrane,    -   selecting and processing nanoparticles to release soluble metal        ions,    -   adding additional soluble metal ions to improve membrane        performance, and    -   testing of nanoparticle membranes and examples.-   Section B: Hybrid TFC membranes including the following additives    used in various combinations:    -   1. Nanoparticles,    -   2. Alkaline earth metal additives,    -   3. Nanotubes,    -   4. Mono-hydrolyzed TMC (mhTMC), and/or    -   5. Other molecular additives.-   Section B1: Improved TFC membranes including the following additives    used in various combinations:    -   1. Nanoparticles,    -   2. Alkaline earth metal additives,    -   3. Nanotubes,    -   4. Mono-hydrolyzed TMC (mhTMC), and/or    -   5. Other molecular additives.-   Section C. Techniques    -   c1. TMC concentration    -   c2 TMC ratio    -   c3. Deflection point.-   Section D. Tables I-XII providing the following information, where    appropriate, for each of 166 examples not included in Sections A-C,    above.    -   MPD & TMC concentrations and ratio,    -   Aqueous and Organic Phase nanoparticles additives,    -   Aqueous and Organic Phase molecular additives,    -   Percentage flux improvement over control membrane without        additives, and    -   Flux (GFD) and Salt Rejection %.-   Section E. Preparation and testing methodology for the example    membranes.

Section A: Improved Nanoparticle TFC Membranes

Referring to FIG. 1, which is not drawn to scale for clarity of thedescription, reverse osmosis (RO) membrane 10 is synthesized using ainterfacial polymerization process on a porous support membrane 12. Twoimmiscible solvents are used, so that a monomer in one solvent reactswith a monomer in the other solvent. The reactions are very fast andrelatively high molecular weights are obtained.

Reinforcing fabric layers 20, woven or nonwoven, and made up ofpolymeric fibers are often employed. In some instances, fabric layer 20may have nanoparticles 22 incorporated for added strength. Fabric layer20 is preferably permeable to water, flat, and without stray fibers thatcould penetrate support 12 or thin film discrimination layer 24. Itshould be thin to decrease cost and to maximize membrane area, strongagainst extension, and mechanically resistant to deformation at highpressures. By adding nanoparticles 22 to the polymer fibers of fabric20, more mechanically robust backings may be created that allow thinner,cheaper, and/or tougher supports to be manufactured.

In FIG. 1, aqueous phase layer 14 is shown with nanoparticles 16dispersed therein on an upper surface of support membrane 12, andorganic phase layer 18 interacts with aqueous layer 14. The interfacebetween these layers is where the polymerization occurs.

In some embodiments, nanoparticles may be selected for their ability torelease metal species such as alkaline earth or aluminum ions. Suchparticles may be dispersed within either the aqueous layer 14 or theorganic phase layer 18, or both. Additional nanoparticles may also bepresent to impact surface properties or further increase performance,for example to improve fouling resistance. Nanoparticles 22 may be thesame or different from nanoparticles 16. Metal ions 16 may be dissolvedwithin either the aqueous layer 14, as shown in FIG. 10, or the organicphase layer 18, as shown in FIG. 11, or in both layers. Metal ions 16may be dissolved within the aqueous layer 14, as shown in FIG. 13.

By dispersing aluminum releasing nanoparticles 16 in the aqueous orpolar solvent 14 and/or organic phase layer 18 before interfacialpolymerization, increased flux is often observed, especially whennanoparticles 16 are processed to enhance solubility of metal ions.Nanoparticles in solution may release aluminum before the polymerizationreaction occurs to aqueous solution 14 or organic solution 18. Thedissolved metal ions are thought to affect the polymerization reactionand ultimately membrane structure leading to improved performance. It isthought that the dissolved metal ions may serve as a template to guidepolymerization leaving spaces or channels for increased water transport.

In FIG. 15, nanoparticles 16 selected to release soluble metal speciesto introduce metal ions 17 into aqueous layer 14, during fabrication maybe dispersed within or on porous support membrane 12. Nanoparticles 16may also be introduced into aqueous layer 14 or organic phase layer 18or both to introduce additional metal ions 17 into aqueous layer 14during fabrication. Additional nanoparticles 17 may also be present toimpact surface properties or further increase performance of membrane10. In some embodiments the interfacial polymerization process at leastone of solutions a) and b) contains nanoparticles that release at least1 ppm of a soluble metal species per 5% (w/w) nanoparticles, based onthe weight of the mixture, and wherein said nanoparticles have beenprocessed to maximize the amount of said soluble metal speciescontributed to the interfacial polymerization mixture.

RO membranes may be fabricated in which nanoparticles are included inthe porous support membrane to release soluble metal ions for theinterfacial polymerization process and/or improve flux flow decline by,perhaps, resisting compaction of the support membranes during reverseosmosis. The nanoparticles may be selected based on their ability torelease 1 ppm or more of soluble metal species into the water containedin the support membrane. It may be advantageous to store the supportmembrane, for example for up to one hour, before interfacialpolymerization on the support membrane between aqueous and organic phasesolutions. It may also be advantageous to form the discrimination layerby contacting the aqueous phase solution to the organic phase solutionon the support membrane for at least 10 seconds, preferably 2 minutesand more preferably 5 minutes after the organic phase solution isapplied.

Referring now to FIG. 16, casting solution 13 on fabric 20 becomessupport membrane 12, after processing. Membrane 12 is typically apolymeric microporous support membrane which in turn is often supportedby nonwoven or woven fabrics, such as fabric 20, for mechanicalstrength. Support membranes 12 are typically 25-250 microns in thicknessand have been found to have the smallest pores located very near theupper surface. Porosity at the surface is often low, for instance from5-15%, of the total surface area.

Nanoparticles 16 may be incorporated into support membrane 12 byincluding nanoparticles 16 with casting solution 13 used to preparesupport membrane 12, or by including nanoparticles 16 within thenonsolvent, e.g. DI water, used to induce phase inversion duringfabrication of support membrane 12.

Referring now to FIG. 17, in addition to providing metal ions 17 toaqueous phase 14, the addition of nanoparticles 16 to support membrane12 may also serve to increase or maintain flux, or at least reduce thedecline over time of the flux, of purified water 28 through membrane 10from reverse osmosis of saltwater 26. During reverse osmosis, theapplication of hydrostatic pressures via saltwater 26 to conventionalthin film composite membranes (TFC) is known to cause a reduction ofmembrane permeability, probably due to compaction of support membrane12. When a polymeric membrane is put under pressure, the polymers areslightly reorganized and the structure is changed, resulting in alowered porosity, increased membrane resistance, and eventually loweredflux. As the applied pressure is increases, so does the extent ofphysical compaction. Generally the flux decline of TFC membranes inbrackish water desalination is around 15-25% and in sea waterdesalination it is as high as 30-40% due to compaction. The compactionproblem in polyamide thin film composite (TFC) reverse osmosis (RO)membranes probably arises mainly due to compaction of the thick porouspolysulfone support layer, membrane 12. The use of nanoparticles 16 inporous support membrane 12 may therefore also reduce flux flow declineover time by, perhaps, resisting or limiting compaction of supportmembrane 12.

By dispersing metal ion releasing nanoparticles 16 in support membrane12 to release metal ions 17 in aqueous solution 14 before or duringinterfacial polymerization, increased flux is often observed in theresultant RO membrane 10. Nanoparticles in solution in aqueous solution14 or organic solution 18 may release metal ions 17 before thepolymerization. Dissolved metal ions 17 are thought to affect thepolymerization reaction and ultimately membrane structure leading toimproved performance. It is thought that the dissolved metal ions 17 mayserve as a template to guide polymerization leaving spaces or channelsfor increased water transport.

During fabrication, porous support membrane 12 including nanoparticles16 dispersed therein, and/or on the surface thereof, can be immersed inan aqueous solution, such as aqueous phase 14, containing a firstreactant (e.g., 1,3-diaminobenzene or “MPD” monomer) to release solublemetal ions 17 therein. Support membrane 12 can then be put in contactwith an organic solution, such as organic phase 18, containing a secondreactant (e.g., trimesoyl chloride or “TMC” initiator). Typically, theorganic or apolar liquid is immiscible with the polar or aqueous liquid,so that the reaction occurs at the interface between the two solutions,e.g. between aqueous and organic phases 14,18 to form a dense polymerlayer on surface of support membrane 12.

Suitable nanoparticles 16 for dispersion in support membrane 12 asdescribed above, include those selected for their ability to releasealkaline earth metals, or other metal species, into organic phase 14during the interfacial polymerization reaction, especially whennanoparticles 16 are processed to enhance solubility of metal ions suchas alkaline earth metals 17.

Porous support membranes 12 are typically kept wet until use.Nanoparticles 16 may be selected to release metal ions 17 which mayenter the water or other solvent contained within or on support membrane12. The amount of metal ions 17 available for the interfacialpolymerization of aqueous phase 14 and organic phase 18 may in somecases be increased by storing support membrane 12, for example in rollform, for a suitable time period such as at least one hour beforefabrication of RO membrane 10.

It may be important to allow sufficient time for metal ions 17 todiffuse from support membrane 12 into aqueous phase 14 before or duringinterfacial polymerization. A time of between 2 seconds and 5 minutes,and preferably between 10 seconds and 2 minutes is currently believed tobe suitable for such diffusion so that metal ions 17 from nanoparticles16 impacts formation of discrimination layer 24 and improves performanceof RO membrane for example by increasing water flux therethrough for thesame applied pressure.

It may be advantageous to pre-process nanoparticles 16 by using sonicenergy from a sonic probe or sonic bath before incorporation thereof insupport membrane 12 and/or further sonicate either aqueous phase 14,organic phase 18 or both just before or during interfacialpolymerization. Sonication processing nanoparticles 16 may includeimmersing a sonic probe directly into casting solution 13 from whichsupport membrane 12 is formed or into organic or aqueous phases 14and/or 18 and/or placing solutions with nanoparticles 16 in a vessel andimmersing the vessel in a sonic bath. Solutions are subjected tosufficient sonic energy from 10 to 60 minutes to aid in the release ofmetal species, such as alkaline earth metal ions 17, into the solution.After sonication, the solution contains additional metal species.Additional sonication time may release additional metal species up tosome limit equilibrium.

Processing of selected nanoparticles 16 may also be accomplished usingshear, cavitation, and impact forces generated by 1 to 60 minutes in aMicrofluidizer (a trademark of the Microfluidics Corp.). Afterprocessing, the solution contains additional metal species that weredissolved from nanoparticles 16.

Processing of selected nanoparticles 16 may be also accomplished using asolution containing nanoparticles 16 in a vessel with a stir bar andusing a stir plate to propel the stir bar in the solution oralternatively using a motorized propeller to stir the solution oralternatively using a lab tray shaker. Stirring or shaking is mosteffective for nanoparticles that have been selected for high solubilityin either the aqueous or the organic phases 14, 18.

Processing of the selected nanoparticles 16 may be accomplished using asolution containing nanoparticles 16 in a vessel and adjusting the pHeither lower than about 6 and more preferably less than about 5 for atleast 30 seconds, to a pH greater than about 8 and more preferablygreater than about 9 for at least 30 seconds. Whether pH is adjustedhigher than about 8 or lower than about 6 may dependent on thesolubility characteristics of the specific type of nanoparticle 16.

The term “molecular additive” encompasses a wide range of additivesincluding metal ions and mHTMC. In FIG. 15-17, preferred concentrationsof molecular additives such as metal ions are from 0.0001% (weightpercent equivalent of 1 ppm) to 5% by weight and more preferred from0.05% to 1% into aqueous layer 14. Processing may enhance nanoparticledissolution, or other techniques for adding molecular additives toassist in achieving the desired concentrations of molecular additives 17in solution. In some embodiments, processed nanoparticles or othercarries may have been broken or partially dissolved using shear,cavitation, or impact forces to maximize said soluble metal speciescontributed to the interfacial polymerization mixture, including amicrofluidizer apparatus. The nanoparticles or other relativelyinsoluble carriers may have been calcined for at least 1 hour at 200° C.or more. The processed carriers can have been shaken in aqueous solutionon a shaker table for at least 1 minute. Carriers may have beenprocessed by subjecting them to sonic energy in a vessel having a sonicprobe within a solution, said energy sufficient to increase the solublemetal species or other molecular additives contributed by the processedcarriers to the interfacial polymerization mixture, e.g., in a vesselsuspended in a sonic bath for at least 5 minutes.

The nanoparticles or other relatively insoluble carriers may have beenprocessed in a solution at a pH lower than about 6 for at least 30seconds or at a pH lower than about 5 for at least 30 seconds. Thenanoparticles or other relatively insoluble carriers may have beenprocessed in a solution at a pH greater than about 8 for at least 30seconds or in a solution at a pH greater than about 9 for at least 30seconds. Nanoparticles or other relatively insoluble carriers may havebeen processed with heat in a solution for at least 5 minutes at atemperature of 40° C. or more. Nanoparticles or other relativelyinsoluble carriers may have been processed with chelating agents insolution to bind soluble metal species or other molecular additives.

Zeolites and other inorganic mineral compounds may also be furtherselected for use as nanoparticles 16 to release molecular additives 17based on the degree of crystallization the nanoparticles 16. Amorphousportions of nanoparticles 16 are typically more soluble than crystallineportions of the nanoparticle and processing can increase solubility. Theamount of crystalline material can be determined through severaltechniques including x-ray crystallography.

Referring now also to FIGS. 2-4, nanoparticles or other insolublecarriers 16 may be included in organic phase or layer 18, both aqueouslayer 14 and organic layer 18, and/or also or only in a layer betweenaqueous phase 14 and support membrane 12 for example in water solution15 in liquid communication with both aqueous layer 14 and the waterwetted surface of support membrane 12. Nanoparticles or other relativelyinsoluble carriers 16 may in fact be in the water wetted surface ofsupport membrane 12 whether or not included in the aqueous layer 14 ororganic layer 18.

Support membrane 12 is typically a polymeric microporous supportmembrane, which in turn is often supported by non-woven or wovenfabrics, such as fabric 20, for mechanical strength. Support membrane 12may conventionally be made from polysulfone or other suitably porousmembranes, such as polyethersulfone, poly(ether sulfone ketone),poly(ether ethyl ketone), poly(phthalazinone ether sulfone ketone),polyacrylonitrile, polypropylene, cellulose acetate, cellulosediacetate, or cellulose triacetate. These microporous support membranes12 are typically 25-250 microns in thickness and may have the smallestpores located very near the upper surface. Porosity at the surface maybe low, for instance from 5-15% of the total surface area.

The preparation of support membrane 12 may begin with the addition ofN-methylpyrrolidone (NMP) solvent (Acros Organics, USA) to a polysulfonepolymer (M, −26,000 from Aldrich, USA) in transparent bead form inairtight glass bottles. Alternatively dimethylformamide (DMF) may beused as the solvent. Nanoparticles 16 may be dispersed in the NMP beforeits addition to the polysulfone polymer. The solution may then beagitated for several hours until complete dissolution is achieved,forming the dope or casting solution 13. Casting solution 13 may then becast or spread over non-woven fabric 20 attached to glass plate 15 via aknife-edge. Glass plate 15 may then be immediately immersed intodemineralized water, which had preferably been maintained at the desiredtemperature. Immediately, phase inversion begins and after severalminutes, non-woven support fabric 20 supporting polysulfone membrane 12may be separated from glass plate 15. Membrane 12 is then washedthoroughly with deionized water and stored in cold conditions untilused. In a continuous coating process, glass plate 15 would not berequired.

Nanoparticles such as zeolites, particularly LTA, may be added tosupport membrane 12 during processing to improve flux for reverseosmosis by, perhaps, improving porosity e.g. at the surface of supportmembrane 12 and/or by making membrane 12 more resistant to compaction.

In some circumstances, nanoparticles or other relatively insolublecarriers 16 may be added to aqueous phase 14 to improve RO membranecharacteristics such as flux without reducing rejection as much asadding nanoparticles 16 to the organic phase 18. Nanoparticles or otherrelatively insoluble carriers 16 may similarly be included in a layerbetween support membrane 12 and discrimination layer 24 as shown belowin FIG. 6. In preferred embodiments, the rejection is at least 99.5% andthe flux is at least 30, 35 or 40 GFD.

Nanoparticles or other relatively insoluble carriers 16 may includes ametallic species such as gold, silver, copper, zinc, titanium, iron,aluminum, zirconium, indium, tin, magnesium, or calcium or an alloythereof or an oxide thereof or a mixture thereof. They can also be anonmetallic species such as Si₃N₄, SiC, BN, B₄C, or TiC or an alloythereof or a mixture thereof. They can be a carbon-based species such asgraphite, carbon glass, a carbon cluster of at least C₂,buckminsterfullerene, a higher fullerene, a carbon nanotube, a carbonnanoparticle, or a mixture thereof.

Suitable zeolites for use as nanoparticles 16 include LTA, RHO, PAU, andKFI. Such synthetic zeolites have different Si/Al ratios, and exhibitdifferent characteristic charge and hydrophilicity and may therefore beselected for RO membranes 10 in different circumstances. Nanoparticles16 may also include zeolite precursors or amorphous aluminosilicates.

Zeolites can be crystalline aluminosilicates with fully cross-linked,open framework structures made up of corner-sharing SiO₄ and AlO₄tetrahedra. A representative empirical formula of a zeolite isM_(2/n)O.Al₂O₃.xSiO₂.yH₂O where M represents the exchangeable cation ofvalence n. M is generally a Group I or II ion, although other metal,non-metal, and organic cations can also balance the negative chargecreated by the presence of Al in the structure. The framework cancontain interconnected cages and channels of discrete size, which can beoccupied by water. In addition to Si⁴⁺ and Al³⁺, other elements can alsobe present in the zeolitic framework. They need not be isoelectronicwith Si⁴⁺ or Al³⁺, but are able to occupy framework sites.Aluminosilicate zeolites typically display a net negative frameworkcharge, but other molecular sieve frameworks can be electricallyneutral.

Aluminosilicate zeolites with a Si:Al ratio less than 1.5:1 arepreferred. Other preferred minerals include Aluminite, Alunite, AmmoniaAlum, Anauxite, Apjohnite, Basaluminite, Batavite, Bauxite, Beidellite,Boehmite, Cadwaladerite, Cardenite, Chalcoalumite, Chiolite,Chloraluminite, Cryolite, Dawsonite, Diaspore, Dickite, Gearksutite,Gibbsite, Halloysite, Hydrobasaluminite, Hydrocalumite, Hydrotalcite,Illite, Kalinite, Kaolinite, Mellite, Montmorillonite, Natroalunite,Nontronite, Pachnolite, Prehnite, Prosopite, Ralstonite, Ransomite,Saponite, Thomsenolite, Weberite, Woodhouseite, and Zincaluminite.

Zeolites and other inorganic mineral compounds may also be furtherselected based on the degree of crystallization. Amorphous portions ofthe nanoparticle are typically more soluble than crystalline portions ofthe nanoparticle and processing can increase solubility: The amount ofcrystalline material can be determined through several techniquesincluding x-ray crystallography. The nanoparticles may have a structurewith greater than 0.5%, 1% or 5% amorphous material by mass within theparticle and may have a surface containing at least 40% of aluminumatoms or oxygen atoms directly bound to aluminum atoms.

Minerals that have similar cage-like framework structures to Zeolites orhave similar properties and/or are associated with zeolites include thephosphates: kehoeite, pahasapaite and tiptopite; and the silicates:hsianghualite, lovdarite, viseite, partheite, prehnite, roggianite,apophyllite, gyrolite, maricopaite, okenite, tacharanite andtobermorite. Thus, minerals similar to zeolites may also be molecularsieves based on AlPO₄. These alum inophosphates,silicoalumino-phosphates, metalloaluminophosphates andmetallosilicoaluminophosphates are denoted as AlPO_(4-n), SAPO-n,MeAPO-n and MeAPSO-n, respectively, where n is an integer indicating thestructure type. AlPO₄ molecular sieves can have the structure of knownzeolites or other structures. When Si is incorporated in an AlPO_(4-n)framework, the product can be known as SAPO. MeAPO or MeAPSO sieves arecan be formed by the incorporation of a metal atom (Me) into anAlPO_(4-n) or SAPO framework. These metal atoms include Li, Be, Mg, Co,Fe, Mn, Zn, B, Ga, Fe, Ge, Ti, and As.

Most substituted AlPO_(4-n)'s have the same structure as AlPO_(4-n), butseveral new structures are only found in SAPO, MeAPO and MeAPSOmaterials. Their frameworks typically carry an electric charge.

Non-zeolite nanoparticles and or other relatively insoluble carriers maybe selected from a list of inorganic mineral compounds that have asolubility product such that preferred concentrations of dissolvedmolecular additives can be achieved. For many compounds, thesesolubility products (Ksp) are well known. For compounds where these arenot known experimentally, molecular additive releasing or otherrelatively insoluble carriers may also be selectable by their counterion. In such cases, compounds may be selected based on the presence ofsulfate, hydroxide or oxide counterions. Solubility of these non-zeolitenanoparticles or other relatively insoluble carriers can be enhancedusing processing.

Particle size is often described in terms of average hydrodynamicdiameter, assuming a spherical shape of the particles or otherrelatively insoluble carriers. Selected nanoparticle or other relativelyinsoluble carriers 16 can have an average hydrodynamic diameter of fromabout 0.1 nm to about 1000 nm, from about 10 nm to about 1000 nm, fromabout 20 nm to about 1000 nm, from about 50 nm to about 1000 nm, fromabout 0.11 nm to about 500 nm, from about 10 nm to about 500 nm, fromabout 50 nm to about 250 nm, from about 200 nm to about 300 nm, or fromabout 50 nm to about 500 nm.

Suitable nanoparticles or other relatively insoluble carriers are oftendispersed in a solution compatible with the aqueous or polar solventthat will be used during interfacial polymerization. (In many caseswater may be used as both the dispersion solvent and the aqueous solventfor use during the reaction). This dispersion largely includes isolatedand individual nanoparticles or other relatively insoluble carriers.Suitable methods for dispersion include stirring, ultrasonication,shaking, use of surfactants or cosolvents, use of Microfluidizer™ (atrademark of the Microfluidics Corp.) material or similar materials, useof mortar and pestle, use of a ball mill or jar mill. In many cases someof the nanoparticles or other relatively insoluble carriers may still beassociated with other nanoparticles or other relatively insolublecarriers. These aggregates may be left in solution, or removed by asuitable technique.

By dispersing nanoparticles or other relatively insoluble carriers inthe aqueous or polar solvent used during interfacial polymerization, TFCmembranes including nanoparticles or other relatively insoluble carriershaving improved performance can be obtained. In particular increasedflux is often observed with TFC membranes prepared with solutionscontaining well dispersed nanoparticles or other relatively insolublecarriers. Inclusion of suitable (e.g. having optimized size, shape,porosity, and/or surface chemistry) nanoparticles or other relativelyinsoluble carriers in the aqueous solution or organic solution, followedby appropriate preparation techniques, can lead to such well dispersedsolutions of nanoparticle or other relatively insoluble carriers. As aresult of using such well dispersed solutions or other relativelyinsoluble carriers films with a high number of nanoparticles or otherrelatively insoluble carriers incorporated in the final membrane can beprepared.

In such a dispersion, nanoparticles or other relatively insolublecarriers 16 can exist either as isolated and individual species or asbuilding blocks incorporated in larger aggregate structures. Thesestructures can be fairly stable and unchanging such as those formedduring synthesis (for instance during calcinations of zeolites) or theycan be transient structures arising from thermodynamics of the carriersand solution. Well dispersed solutions, that is solutions in which thenanoparticles or other relatively insoluble carriers are well dispersed,primarily contain isolated and individual nanoparticles or otherrelatively insoluble carriers rather than aggregates of such particles.In particularly, it may be preferable to use a solution containingprimarily isolated and individual nanoparticles or other relativelyinsoluble carriers and very few larger structures such as aggregates. Inthis manner the largest number of isolated nanoparticles or otherrelatively insoluble carriers can be incorporated within the finalmembrane and/or serve to optimize the structure of the membrane.

Solutions in which nanoparticles or other relatively insoluble carriersare well dispersed, without substantial aggregates, can be attained bythe use, for example of nanoparticles of zeolite LTA in the aqueous orpolar solvent 14 that will be used during interfacial polymerization.(In many cases water is used as both the dispersion solvent and theaqueous solvent for use during the reaction). This dispersion largelyhas isolated and individual nanoparticles. This particular solution iswell dispersed due to the hydrophilic surface of LTA and its stronginteraction with water, its small size of less than 1 micron. Suitablemethods for causing the desired dispersion include stirring,ultrasonication, shaking, use of surfactants or cosolvents, use of aMicrofluidizer™ type material, use of mortar and pestle, use of a ballmill or jar mill. In particular, high intensity ultrasonication or theMicrofluidizer performed for a sufficient time period results in welldispersed solutions.

Referring now to FIGS. 1-4, aqueous phase 14 used during interfacialpolymerization may also include one of the reactants, nanoparticles, orother relatively insoluble carriers, and processing aids such assurfactants, drying agents, catalysts, coreactants, cosolvents, etc.

Generally, the polymer matrix which forms discrimination layer 24 can beprepared by reaction of two or more monomers. The first monomer can be adinucleophilic or a polynucleophilic monomer and the second monomer canbe a dielectrophilic or a polyelectrophilic monomer. That is, eachmonomer can have two or more reactive (e.g., nucleophilic orelectrophilic) groups. Both nucleophiles and electrophiles are wellknown in the art, and one of skill in the art can select suitablemonomers for this use. The first and second monomers can also be chosenso as to be capable of undergoing an interfacial polymerization reactionto form a polymer matrix (i.e., a three-dimensional polymer network)when brought into contact. The first and second monomers can also bechosen so as to be capable of undergoing a polymerization reaction whenbrought into contact to form a polymer product that is capable ofsubsequent crosslinking by, for example, exposure to heat, lightradiation, or a chemical crosslinking agent.

The first monomer can be selected so as to be soluble in a polar liquid,preferably water, to form a polar mixture. Generally, the difunctionalor polyfunctional nucleophilic monomer can have primary or secondaryamino groups and can be aromatic (e.g., a diaminobenzene, atriaminobenzene, m-phenylenediamine, p-phenyenediamine,1,3,5-triaminobenzene, 1,3,4-triaminobenzene, 3,5-diaminobenzoic acid,2,4-diaminotoluene, 2,4-diaminoanisole, and xylylenediamine) oraliphatic (e.g., ethylenediamine, propylenediamine, piperazine, andtris(2-diaminoethyl)amine). In a yet further example, the polar liquidand the first monomer can be the same compound; that is, the firstmonomer can provided and not dissolved in a separate polar liquid.

Examples of suitable amine species include primary aromatic amineshaving two or three amino groups, for example m-phenylene diamine, andsecondary aliphatic amines having two amino groups, for examplepiperazine. The amine can typically be applied to the microporoussupport as a solution in a polar liquid, for example water. Theresulting polar mixture typically includes from about 0.1 to about 20weight percent, preferably from about 0.5 to about 6 weight percent,amine. Once coated on a porous support, excess polar mixture can beoptionally removed. The polar mixture need not be aqueous, but the polarliquid should be immiscible with the apolar liquid. Although water is apreferred solvent, non-aqueous polar solvents can be utilized, such asacetonitrile and dimethylformamide (DMF).

The polar mixture can typically be applied to microporous supportmembrane 12 by dipping, immersing, coating or other well knowntechniques. Once coated on porous support membrane 12, excess polarmixture can be optionally removed by evaporation, drainage, air knife,rubber wiper blade, nip roller, sponge, or other devices or processes.

Organic phase 18 used during interfacial polymerization may also includeone of the reactants, nanoparticles, or other relatively insolublecarriers, and processing aids such as catalysts, co-reactants,co-solvents, etc.

A second monomer can be selected so as to be miscible with the apolar(organic) liquid forming an apolar mixture, although for monomers havingsufficient vapor pressure, the monomer can be optionally delivered froma vapor phase. The second monomer can optionally also be selected so asto be immiscible with a polar liquid. Typically, the second monomer canbe a dielectrophilic or a polyelectrophilic monomer. The electrophilicmonomer can be aromatic in nature and can contain two or more, forexample three, electrophilic groups per molecule. The second monomer canbe a trimesoyl halide. For the case of acyl halide electrophilicmonomers, acyl chlorides are generally more suitable than thecorresponding bromides or iodides because of the relatively lower costand greater availability.

Suitable polyfunctional acyl halides include trimesoyl chloride (TMC),trimellitic acid chloride, isophthaloyl chloride, terephthaloyl chlorideand similar compounds or blends of suitable acyl halides. As a furtherexample, the second monomer can be a phthaloyl halide.

The polyfunctional acyl halide can be dissolved in the apolar organicliquid in a range of, for example, from about 0.01 to about 10.0 weightpercent or from about 0.05 to about 3 weight percent. Suitable apolarliquids are capable of dissolving the electrophilic monomers (e.g.polyfunctional acyl halides) and which are immiscible with a polarliquid (e.g., water). In particular, suitable apolar liquids can includethose which do not pose a threat to the ozone layer and yet aresufficiently safe in terms of their flashpoints and flammability toundergo routine processing without having to undertake extremeprecautions. These include C₅-C₇ hydrocarbons and higher boilinghydrocarbons, i.e., those with boiling points greater than about 90° C.,such as C₈-C₂₄ hydrocarbons and mixtures thereof, which have moresuitable flashpoints than their C₅-C₇ counterparts, but are lessvolatile. The apolar mixture can typically be applied to the microporoussupport membrane 12 by dipping, immersing, coating or other well knowntechniques.

In one embodiment, the polyfunctional acyl halide monomer (also referredto as acid halide) is coated on support membrane 12, typically fromorganic phase solution 18. Amine solution 14 is typically coated firston porous support 12 followed by acyl halide solution 18. The monomerscan react when in contact, thereby polymerizing to produce a polymer(e.g., polyamide) matrix film discrimination layer 24 at the uppersurface of support structure 12. Although one or both of thepolyfunctional amine and acyl halide layers can be applied to poroussupport 12 from a solution, such as aqueous and organic solutions 14 and18, they can alternatively be applied by other means such as by vapordeposition, or heat.

In another embodiment, by dissolving an molecular additives 16 in theaqueous or polar solvent 14 and/or organic phase layer 18 (or both) usedduring interfacial polymerization before contact therebetween, increasedflux is often observed through membrane 10 during reverse osmosiswithout substantially affecting salt rejection.

Suitable earth alkaline metal species or other molecular additives 16include salts or compounds that are dissolvable to some extent in eitherthe aqueous phase layer 14 or the organic phase layer 18 or both.Different species may be used for the aqueous phase layer 14 and theorganic phase layer 18. In many embodiments the beta-diketonate may bean acetoacetonate. Preferred species in the organic phase for aluminumspecies include Al(acac)₃, wherein (acac) is acetylacetonate, abidentate ligand. Preferred species in the aqueous layer include sodiumaluminate, aluminum citrate, and aluminum camphorsulfonate. Preferredspecies for other molecular additives including earth alkine metals areset forth in Tables I-XII herein below.

Preferred concentrations of the metal species are from 0.005 wt. % to 5wt. % by weight and more preferred from 0.05 wt. % to 1 wt. % in eitheraqueous layer 14 or organic layer 18.

When molecular species are used in the organic phase 18, it may bebeneficial to sonicate the solution. Sonication may serve to betterdisperse the molecular species. Sonication may also serve to drivereactions that would otherwise require higher temperatures, catalysts,or initiators to occur.

In some cases, performance can be further improved by the addition of arinse in a high pH aqueous solution after RO membrane 10 is formed. Forexample, membrane 10 can be rinsed in a sodium carbonate solution. ThepH is preferably from 8-12, and exposure time may vary from 10 secondsto 30 minutes or more. The rinse may alternatively be a hot water rinsewith temperatures of 60-98 C. The rinse may also include a chlorinespecies such as sodium hypochlorite.

Interfacial polymerization occurs at the interface between aqueous phaselayer 14 and organic phase layer 18 to form discrimination layer 24, asshown in FIGS. 5, 6, 8, and 9. Discrimination layer 24 may typically bea composite polyamide membrane prepared by coating porous supportmembrane 12 with a polyfunctional amine monomer, most commonly coatedfrom aqueous phase solution 14. Although water is a preferred solvent,non-aqueous solvents can be utilized, such as acetonitrile anddimethylformamide (DMF). A polyfunctional acyl halide monomer (alsoreferred to as acid halide) may then subsequently be coated on supportmembrane 12, typically from organic phase solution 18. The aminesolution 14 is typically coated first on 12 porous support followed byacyl halide solution 18. The monomers can react when in contact, therebypolymerizing to produce a polymer (e.g., polyamide) matrix film 24 atthe upper surface of support structure 12. Although one or both of thepolyfunctional amine and acyl halide can be applied to porous support 12from a solution, such as aqueous and organic solutions 14 and 18, theycan alternatively be applied by other means such as by vapor deposition,or heat.

In some embodiments, by dispersing molecular additives such as earthalkaline and other metals 16 in the aqueous or polar solvent 14 and/ororganic phase layer 18 used during interfacial polymerization, increasedflux is often observed. Nanoparticles and other relatively insolublecarriers in solution may release molecular additives before thepolymerization reaction occurs to the aqueous solution 14 or organicsolution 18. The dissolved molecular additive is thought to affect thepolymerization reaction and ultimately membrane structure leading toimproved performance. It is thought that the dissolved molecularadditive may serve as a template to guide polymerization leaving spacesor channels for increased water transport. Suitable nanoparticles orother relatively insoluble carriers for dispersion include thoseselected for their ability to release the desired molecular additives ineither the organic phase or the aqueous phase of an interfacialpolymerization reaction.

The solubility constant may be considered to be the mass of molecularadditive in solution (e.g. additive 17) divided by the initially usedmass of nanoparticle or other carrier in the same solution. For example,a 5 wt % solution of nanoparticle that gives 1 ppm of dissolved metalspecies would give a 0.002% solubility constant, and a 1% solutiongiving 1 ppm give 0.01%. Solubility of minerals can be used as a generalguide to the solubility of those same mineral nanoparticles.

However, smaller nanoparticles have greater surface exposure per unitmass and smaller nanoparticles increase the number of exposed metal orother atoms per unit area over and above a simple surface area effect.Greater exposure of such atoms or molecules in solution may increasesolubility of the desired additives. Presence of counter ions such assulfate, hydroxide and fluoride may also increase solubility.

Mineral solubility can be enhanced using processing.

Calcined zeolite nanoparticles may increase additive solubility becausethe calcining process may increase the amount of additive in pores andhence available for exchange.

Zeolites and other inorganic mineral compounds can be further selectedbased on the degree of crystallization. Amorphous portions of thenanoparticle are more soluble than crystalline portions of thenanoparticle. The amount of crystalline material can be determinedthrough several techniques including x-ray crystallography.

Non-zeolite nanoparticles may be selected from a list of inorganicmineral compounds that have a solubility product such that preferredconcentrations of dissolved metal species or other additives can beachieved. For many compounds these solubility products (Ksp) are wellknown. For compounds where these are not known experimentally, additivereleasing nanoparticles can also be selected by their counter ion. Inthis case compounds are selected based on the presence of sulfate,hydroxide or oxide counter ions.

Preferred concentrations of the additives dissolved from nanoparticlesare from 0.0001% to 5% by weight, and more preferred from 0.05 wt. % to1 wt. % in either aqueous layer 14 or organic layer 18.

Non-zeolite hydrocarbon nanoparticles can be selected based on thepresence of the desired additive in the ash of these hydrocarbons. Thepresence of the additive in the ash of these compounds may relate to theability of these compounds to release the additive in solution. Thesehydrocarbon nanoparticles are preferably included in the organic phase18.

It is often beneficial to sonicate the solution. Sonication may serve tobetter disperse the nanoparticles. Sonication may also serve to drivereactions that would otherwise require higher temperatures, catalysts,or initiators to occur.

The porous support structure can be immersed in an aqueous solutioncontaining a first reactant (e.g., 1,3-diaminobenzene or “MPD” monomer).The substrate can then be put in contact with an organic solutioncontaining a second reactant (e.g., trimesoyl chloride or “TMC”monomer). Typically, the organic or apolar liquid is immiscible with thepolar or aqueous liquid, so that the reaction occurs at the interfacebetween the two solutions to form a dense polymer layer on the supportmembrane surface.

Representative conditions for reaction of an amine (e.g., MPD) with anelectrophile (e.g., TMC) to form a polyamide thin film compositemembrane, employ a concentration ratio of MPD to TMC of about 10-20,with the MPD concentration being about 1 to 6 weight percent of thepolar phase (aqueous phase 14). The polymerization reaction can becarried out at room temperature in an open environment, or thetemperature of either the polar or the apolar liquid, or both, may becontrolled. Once formed, the dense polymer layer, which becomesdiscrimination layer 24, can advantageously act as a barrier to inhibitcontact between the reactants and to slow the reaction. Hence, aselective dense layer is formed which is typically very thin andpermeable to water, but relatively impermeable to dissolved, dispersed,or suspended solids, such as salts to be removed from saltwater orbrackish water in use to produce purified water. This type of membraneis conventionally described as a reverse osmosis (RO) membrane.

Once the polymer layer is formed, the apolar liquid can be removed byevaporation or mechanical removal. It is often convenient to remove theapolar liquid by evaporation at elevated temperatures, for instance in adrying oven.

In some cases, performance can be further improved by the addition of arinse step using a high pH aqueous solution after RO membrane 10 isformed. For example, membrane 10 can be rinsed in a sodium carbonatesolution. The pH is preferably from 8-12, and exposure time may varyfrom 10 seconds to 30 minutes or more.

Referring now to FIG. 6, when used for saltwater purification, saltwater26 may be applied under pressure to discrimination layer 24 includingnanoparticles 16. Purified water 28 then passes through porous supportmembrane 12 and fabric layer 20 if present.

Referring now also to FIG. 9, nanoparticles 16 may also, or only, bepresent between discrimination layer 24 and the top surface of supportmembrane 12.

Referring now to FIGS. 5, 6, and 8, nanoparticles can be included withinmembranes for several reasons, for instance to increase permeability, toalter surface chemistry, to alter roughness or morphology, or to enableanti-bacterial activity and particularly to reduce fouling especially inthe presence of other molecular additives. For these and otherapplications it may be useful to increase the number of nanoparticleswithin RO membrane 10. The percent of the surface of RO membrane 10containing nanoparticles 16 can be measured by any suitable technique.For nanoparticles 16 of zeolite LTA, this incorporation can effectivelybe measured by isolating the thin film of discrimination layer 24 andusing transmission electron microscopy (TEM) to measure the percentageof the membrane containing nanoparticles.

Using well dispersed nanoparticle solutions, membranes with more than 5wt. %, 10 wt. % or even 20 wt. % incorporation of nanoparticle zeoliteLTA can be prepared. In some embodiments at least 20% of the membranesurface area consists of nanoparticles.

Surface properties of RO membrane 10, such as hydrophilicity, charge,and roughness, typically correlate with surface fouling of RO membrane10. Generally, membranes with highly hydrophilic, negatively charged,and smooth surfaces yield good permeability, rejection, and anti-foulingbehavior. The more important surface attributes of RO membranes topromote fouling resistance are hydrophilicity and smoothness. Membranesurface charge can also be a factor when solution ionic strength issignificantly less than 100 mM, because at or above this ionic strength,electrical double layer interactions are negligible. Since many ROapplications involve highly saline waters, one cannot always rely onelectrostatic interactions to inhibit foulant deposition. Moreover, ithas been demonstrated that polyamide composite membrane fouling bynatural organic matter (NOM) is typically mediated by calciumcomplexation reactions between carboxylic acid functional groups of theNOM macromolecules and pendant carboxylic acid functional groups on themembrane surface.

To prevent scratching of the membrane surface or alter adsorption,hydrophilic polymer layer 30 may be applied to the surface of membrane10. For example, a solution of polyvinylalcohol in water may be appliedto the surface of membrane 10 followed by a heat cure.

In some instances, membranes such as RO membrane 10 may be used todesalinate waters containing materials which tend to accumulate on themembrane surface, decreasing the apparent permeability. These materialscan include but are not limited to natural organic matter, partiallyinsoluble inorganic materials, organic surfactants, silt, colloidalmaterial, microbial species including biofilms, and organic materialseither excreted or released from microbial species such as proteins,polysaccharides, nucleic acids, metabolites, and the like. This drop inpermeability is often smaller for nanocomposite membranes as describedherein than for membranes prepared by prior conventional techniques, dueto a decreased amounts, density, viability, thickness and/or nature ofthe accumulated material,

This improvement in fouling resistance is, in part, related to theincreased hydrophilicity of nanocomposite RO membranes 10. The increasedhydrophilicity of TFC membrane 10 can be measured by the equilibriumcontact angle of the membrane surface with a drop of distilled water ata controlled temperature. TFC membrane 10 can have a contact angle thatis reduced by 5°, 10°, 15°, 25° or more, relative to a similarlyprepared membrane without nanoparticles. The equilibrium contact anglecan be less than 45°, less than 40°, than 37°, or even less than 25°.

An additional processing step may then be performed to increase thenumber of nanoparticles 16 on the surface of support membrane 12. Thisstep can include using pressure or vacuum to pull solution throughmembrane 10, causing nanoparticles 16 to build up at the surface ofsupport membrane 12, or can include evaporation of the amine solutionleading to deposition of nanoparticles 16 on the surface of supportmembrane 12. Since the final number of nanoparticles 16 on the surfaceof RO membrane 10 will often impact performance, the coating thicknessof the solution evaporation and the concentration method are allimportant to control.

Referring now also to FIGS. 8 and 9, in some embodiments, somenanoparticles 16 may be located at the interface between supportmembrane 12 and thin polymer film of discrimination layer 24, whether ornot they are included in discrimination layer 24. At this location atthe surface of membrane 12, nanoparticles 16 can reduce the resistanceof flow by creating channels and flow paths between discrimination layer12 and the microporous pores at the surface of support membrane 12.Because of the relatively low density of pores at the surface of themicroporous support membrane 12, reducing the resistance at thislocation can increase the membrane permeability of RO membrane 10 whilemaintaining the rejection characteristics.

In some embodiments, some nanoparticles 16 are located within the thinpolymer film of discrimination layer 24. In these cases, the interfacialpolymerization may occur around and eventually incorporate nanoparticles16. This can lead to additional flow paths through nanoparticles 16leading to increased flow. In some instances this may lead to analteration of the polymer film adjacent to nanoparticles 16 withindiscrimination layer 24, increasing the polymer film's ability topermeate water and retain solutes. This impact on adjacent polymer canoccur in the area up to 10 nm, 1 micron, and even up to 100 microns froma particular nanoparticle 16. In such a way, dramatic increases inperformance can be obtained by relatively few incorporated nanoparticles16.

In some instances nanoparticles 16 affect the polymer itself before andduring the reaction and alter the film chemistry and/or morphologyleading to improved properties without incorporation of nanoparticles 16into RO membrane 10.

In many cases it has been found that smaller diameters of nanoparticles16 may give improved performance of thin film nanocomposite RO membrane10. It is believed that larger nanoparticles and microparticles can leadto unsupported areas of the thin film polymer as well as tears in thethin film. These small tears can result in leakage through the film anda reduction in solute rejection. Use of smaller nanoparticles 16 allowsa flux response with the smallest change in rejection characteristics ofRO membrane 10.

Concentration of the selected nanoparticle 16 can also be important inperformance of RO membrane 10. In many cases a higher concentration ofnanoparticles 16 will lead to more incorporation within discriminationlayer 24, and thus give a larger increase in flux. However above asufficiently high concentration (e.g., more than 0.2 wt. %, more than0.5 wt. %, more than 1 wt. %, or more than 5 wt. %) there is little orno added benefit. In these cases, there may be an optimum concentrationgiving the largest flux response with a negligible decrease in saltrejection, which may be determined by a person of skill in this art. Inother cases, it appears that only very small concentrations ofnanoparticles 16 are needed to enhance membrane performance and anyfurther increase in the concentration of nanoparticles will have littleor no additional effect. In these cases, the smallest amount (preferablyless than 0.2 wt., less than 0.1 wt. %, less than 0.05 wt. %, less than0.01 wt. %) that gives a reproducible performance improvement fromresulting RO membrane 10 may be selected. In such situations,nanoparticles 16 are often assisting, templating, and or altering theformation of the polymer itself, and it is the change in the finalpolymer membrane of discrimination layer 24 which gives the performancechange.

As shown above it can be useful to obtain nanoparticles 16 of a tightersize distribution by controlling what may be called polydispersity. Onemeans of doing this is through the use of a centrifuge. In a centrifuge,particles of larger mass have a faster settling velocity and formsediment at the bottom of a container while the remaining particles stayin solution. By removing the remaining liquid or the sediment both adifferent size and dispersity can be obtained, e.g. nanoparticles havinga smaller average size and a smaller range of sizes.

Another method of improving polydispersity is through the use ofmicrofluidization. Polydispersity can be calculated by dividing thevolume average particle diameter by the number average particlediameter. A polydispersity approaching 1 indicates a tight range ofsizes, while a bigger number indicates a larger range of sizes.Preferred polydispersities are less than 10, 5, 2, 1.5, 1.25, and mostpreferably less than 1.1. For example using sonication alone on sampleof 100 nm LTA lead to a dispersion with a polydispersity of 62.4, whileuse of sonication followed by microfluidization and centrifugation leadto a polydispersity of 1.7. A separate sample of 400 nm LTA aftersonciation and microfluidization had a polydispersity of 1.53.

Molecular Additives

Referring now to FIGS. 22 and 23, molecular additives 16 may bedissolved within the aqueous phase layer 14 as shown in FIG. 22, or inthe organic phase layer 18 as shown in FIG. 23. Referring nowparticularly to FIG. 24, when RO membrane 10 is used for saltwaterpurification, saltwater 26 may be applied under pressure todiscrimination layer 24. Purified water 28 then passes through poroussupport membrane 12 and fabric layer 20, if present. While not willingto be bound by theory, molecular additive 16 may become involved withthe formation of the structure of the polymer forming discriminationlayer 24 during interfacial polymerization and/or may not be present indiscrimination layer 24 during operation of membrane 10.

By dissolving molecular additive 16 in aqueous or polar solvent 14and/or organic phase layer 18 (or both) used during interfacialpolymerization, increased flux is often observed through membrane 10during reverse osmosis without substantially affecting salt rejection.

While not wishing to be bound by theory, it is believed that membrane 10transports water by taking in water and providing conduits for waterdiffusion. These conduits within membrane 10 may be a result of the freevolume in the polymer film and may be considered to be interconnected,atom-sized or larger voids within the polymer film. Membrane 10 madewith metal or other molecular additive 16 may have increased free volumeand thus may be capable of transporting water at a faster rate than amembrane prepared without metal other molecular additive 16. Metal othermolecular additive 16 may initially be stable in solution, but HCl maybe released from the polymerization reaction, metal additive 16 may beprotonated and begin to precipitate, and this precipitation may give offheat at the locus of the polymerization. This heat may affect theaggregation of the forming polymer chains and may result in an alteredstructure that may have increased free volume potentially capable oftaking in, and passing, more water. The ability to transport waterthrough TFC membrane 10 may be thought of as a product of diffusion andthe amount of water within membrane 10, this increased water uptake mayresult in increased permeability.

A molecular additive may be an at least partially soluble compoundcontaining a central atom having a Pauling electronegativity of lessthan about 2.5. Molecular additives that have been previously beendescribed have in some cases been relatively inefficient at increasingmembrane permeability. In general the ligand is bound to an elementselected from Groups 2-15 of the Periodic Table (IUPAC). In someembodiments the element selected from the group consisting of Groups3-15 and Rows 3-6 of the Periodic Table (IUPAC), preferably Groups 3-14and Rows 3-6 of the Periodic Table. In some embodiments, the metal maybe aluminum, gallium, indium, vanadium, molybdenum, hafnium, cobalt,ruthenium, iron, chromium, cadmium, tin, berylium, palladium, ytterbium,erbium, praseodymium, copper, zinc, magnesium, calcium, or strontium.

We have found that by adjusting the concentration of the reagents usedto prepare the membrane to specific ranges, the molecular additives canbe made to work more efficiently. More specifically, the concentrationof TMC has been found to alter the effectiveness of molecular additives.Using concentrations of TMC 50% to 500% higher than commonly used in theindustry (for example 0.1%) results in molecular additives giving asignificantly larger increase in flux.

While using higher TMC concentrations, it may also be useful to adjustMPD concentrations, so that the ratio of MPD/TMC is kept belowapproximately 35/1. When this ratio is allowed to get too high, membranerejection begins to suffer, for example membranes 148, 156, and 164. Insome embodiments the TMC concentration in a) is 0.2-0.6% (w/w),preferably 0.3-0.5% (w/w). In some embodiments the TMC to monohydrolyzedTMC ratio in b) is from 50:1 to 15:1. In some embodiments the b)contains MPD, and the ratio of MPD/TMC is from 5-35 or from 5-25, orfrom 30-35.

B.5 Other Molecular Additives

Suitable molecular additives for additive 16 include compoundscontaining a central atom having a Pauling electronegativity of lessthan about 2.5 Particlulary preferred are Al(acac)₃, Ga(acac)₃,In(acac)₃, V(acac)₃ and other aluminum, galium, indium or vanadiumbeta-diketonate complexes that are dissolvable to some extent in eitherthe aqueous phase layer 14 or the organic phase layer 18 or both

Preferred concentrations of the metal additive complex 16 are from0.005% to 5% by weight and more preferred from 0.025% to 0.25% inorganic layer 18. It may be beneficial to sonicate the solution.Sonication may serve to better disperse the metal in the organicsolution 18. Sonication may also serve to drive reactions that wouldotherwise require higher temperatures, catalysts, or initiators tooccur. It may also be useful to apply cosolvents to better solvate themetal complex. Preferred cosolvents are those that are able to formclear solutions of the beta diketonate metal complex before dilution.Particularly preferred are aromatic solvents including benzene, toluene,xylene, mesitylene, or ethyl benzene. These cosolvents are preferablyused at sufficiently low concentration to not negatively affect membraneperformance.

Improved resistance to accumulation for TFC membranes can in part berelated to increased hydrophilicity of these membranes. The increasedhydrophilicity can be measured by the equilibrium contact angle of themembrane surface with a drop of distilled water at a controlledtemperature. Membranes prepared with metal complex 16 present duringpolymerization can have a contact angle that is reduced by 5, 15, oreven 25 or more degrees relative to a similarly prepared membranewithout the metal complex. The equilibrium contact angle can be lessthan 45°, less than 40°, or even less than 25°.

Preliminary Membrane Testing

Separation Efficacy

Membrane performance may be measured in a flat sheet cell testapparatus. Testing may be conducted at a Reynolds number of 2500, sothat build up of rejected solutes at the membrane surface leads to aconcentration no more than 10% higher than that in the bulk. All testingmay be performed on 32,000 ppm NaCl in deionized (DI) or RO water, at25° C. and 800 psi. Membranes may be run for 1 hour before performancecharacteristics (e.g. water flux and salt rejection) are measured.

Contact Angle

Contact angles may be those of DI water at room temperature. Membranesmay be thoroughly rinsed with water, and then allowed to dry in a vacuumdesiccator to dryness. Membranes 10 may be dried in a vertical positionto prevent redeposition of any extracted compounds that may impactcontact angle. Due to the occasional variability in contact anglemeasurements, 12 angles may be measured with the high and low anglesbeing excluded and the remaining angles averaged.

EXAMPLE A

Two aqueous solutions of 3.2 wt % MPD, 4.5 wt % triethylammoniumcamphorsulfonate (TEACSA) and 0.06 wt % sodium lauryl sulfate (SLS) inDI water were prepared, one of them also contained 0.1% of LTA (150 nmdiameter). The solution with LTA was sonicated for 30 mins. An Isopar Gsolution with 0.3 wt % TMC was also prepared.

A piece of wet polysulfone support was placed flat on a clean glassplate. An acrylic frame was then placed onto the membrane surface,leaving an area for the interfacial polymerization (IP) reaction to takeplace.

Then 50 mL of an aqueous MPD solution prepared as described previouslywas poured onto the framed membrane surface and remained there for 1minute. The solution was drained by tilting the frame until no moresolution dripped from the frame.

The frame was taken off, and was left horizontally for at least 4minutes at which point most of the surface water had evaporated. Themembrane was then clamped with the glass plate in four corners. An airknife was used to finish drying of the membrane surface. The membranewas reframed using another clean and dry acrylic frame and kepthorizontally for 1 minute.

Organic solution (50 mL of 0.3 wt % TMC/Isopar G solution) was pouredonto the framed membrane surface and remained there for 2 min. Thesolution was drained by tilting the frame (vertically) till no solutiondripped from the frame. The acrylic frame was removed, and the membranewas kept horizontally for 1 minute.

The membrane was clamped with the glass plate (four corners), and an airknife was used to dry the membrane surface.

LTA Flux (400 nm) (gfd) Rejection   0% 19.10 99.12% 0.10% 34.05 97.50%

EXAMPLE B

A continuous coating process: an aqueous dispersion of LTA (300 nm) wasadded to an aqueous solution of composition similar to that used in alaboratory batch reaction (4 wt. % MPD). The final solution turbiditywas 21 nephelometric turbidity units (NTU). All other solutions andprocessing conditions were unchanged. This continuous process includedbrief application of a vacuum, which led to the concentration of LTAparticles at the surface of the support membrane.

LTA Flux Contact (300 nm) (gfd) Rejection angle none 17.7 99.40% 50.7 21NTU 26.9 98.80% 36.7

EXAMPLE C

Two aqueous solutions of 4.0 wt % MPD, 4.5 wt % TEACSA and 0.2 wt % SLSin DI water were prepared, one also contained 0.05 wt. % of LTA (80 nmdiameter). The solution with LTA was sonicated for 30 mins. An Isopar Gsolution with 0.3 wt % TMC was also prepared.

A piece of wet polysulfone support was placed flat on a clean glassplate. An acrylic frame was then placed onto the membrane surface,leaving an area for the IP reaction to take place.

An aqueous MPD solution (50 ml) prepared as described previously waspoured onto the framed membrane surface and remained for 1 minute. Thesolution was drained by tilting the frame until no solution dripped fromthe frame.

The frame was taken off, and was left horizontally for at least 4minutes at which point most of the surface water had evaporated. Themembrane was then clamped with the glass plate in four corners. An airknife was used to finish drying of the membrane surface. The membranewas reframed using another clean and dry acrylic frame and kepthorizontally for 1 minute.

Organic solution (50 mL of 0.3 wt % TMC/Isopar G solution) was pouredonto the framed membrane surface and remained for 2 minutes. Thesolution was drained by tilting the frame (vertically) until no solutiondripped from the frame. The acrylic frame was removed, and the membranewas kept horizontally for 1 minute.

The membrane was then dried at 95° C. for 6 minutes.

LTA (80 nm) Flux (gfd) Rejection   0% 20.7 99.50% 0.05% 22.5 99.62%

Metal-Releasing Nanoparticles

EXAMPLE D

Template-free zeolite LTA nanoparticles in an aqueous dispersion werefound to have aluminum content after being subjected to impact,cavitation and shear forces in a microfluidizer. The dispersioncontained approximately 39 weight percent LTA made with double distilledwater. When measured using ICP analysis, the solution had an aluminumcontent of 130.9 parts per million (ppm). This aluminum content islikely related to aluminum dissolution in the aqueous dispersion basedon the data shown in Example 5. A similar dispersion of templatedzeolite LTA nanoparticles (5%) showed an aluminum content of 2.9 ppm.

EXAMPLE E

As shown in Table 1, zeolite LTA (0.05 wt. %) prepared by two differentmethods produces two different Si:Al ratios and two differentsolubilities in double deionized water (DDI) at room temperature ofapproximately 20 degrees Celsius when shaken on a laboratory shakertable for multiple days. Although not tested as long (Table I) zeoliteFAU (0.05 wt. %) shows results that are consistent with the zeolite LTAdata.

TABLE 1 Comparison of Zeolite LTA, Si:Al Ratio and Shaker DissolutionShaker Dissolution Aluminum Framework parts per million plateau MaterialSi:Al Ratio in 500 ml DDI water solution Zeolite LTA (template-free)  1:1 35.90* Zeolite LTA (template) 1.5:1 <0.1** Zeolite FAU ~2.5<0.1*** *Average of 77 to 160-day data; **Average of 1 to 84-day data;***2-day data

EXAMPLE F

As shown in Table 2, membranes prepared from nanoparticles withdiffering Si:Al ratios have different flux as expressed in gfd (gallonsper square foot of membrane per day). Membranes were prepared asfollows:

Two aqueous solutions of 4.0 wt % MPD, 4.5 wt % TEACSA and 0.2 wt. % SLSin DI water were prepared, one also contained 0.05 wt. % of zeolitenanoparticles. The solution with nanoparticles was sonicated for 30minutes. An Isopar G solution with 0.3 wt % TMC was also prepared.

A piece of wet polysulfone support was placed flat on a clean glassplate. An acrylic frame was then placed onto the membrane surface,leaving an area for the IP reaction to take place.

An aqueous MPD solution 50 mL prepared as described previously waspoured onto the framed membrane surface and remained for 1 min. Thesolution was drained by tilting the frame till no solution dripped fromthe frame.

The frame was taken off, and was left horizontally for at least 4minutes at which point most of the surface water had evaporated. Themembrane was then clamped with the glass plate in four corners. An airknife was used to finish drying of the membrane surface. The membranewas reframed using another clean and dry acrylic frame and kepthorizontally for 1 min.

Organic solution (50 mL of 0.3 wt % TMC/Isopar G solution) was pouredonto the framed membrane surface and remained for 2 min. The solutionwas drained by tilting the frame (vertically) until no solution drippedfrom the frame. The acrylic frame was removed, and the membrane was kepthorizontally for 1 minute.

The membrane was then dried at 95° C. for 6 minutes.

TABLE 2 Comparison of Membrane Flux Increase with Nanoparticle TypePercentage increase of flux over similarly made control membraneswithout nanoparticles. Increased Membrane Framework Flux withNanoparticles Material Si:Al Ratio (gfd) Zeolite LTA (template-free)  1:1 13% Zeolite LTA (template) 1.5:1 9% Zeolite KFI 2.2:1 0%

In another experiment under similar conditions, zeolite concentrationwas increased to 0.1 wt % and the flux increase was 50%.

EXAMPLE G

In a continuous coating process; an aqueous dispersion of LTA preparedby sonicating a 5% solution of LTA in water for 5 minutes, followed by20 minutes of microfluidization, and stirring overnight, was added to anaqueous solution of 4% MPD, 4.5% TEACSA, and 0.2% SLS. An organicsolution of 0.3% TMC in Isopar G was also prepared. The continuousprocess followed the same steps and order of solution coating, removal,and drying as detailed in example F.

LTA Flux (gfd) Rejection   0% 17.7 99.4% 0.10% 24.8 98.9%

All performance data unless otherwise noted was obtained from flat sheettesting on NaCl (32,000 ppm) in DI water tested at 800 psi after 1 hourof running.

EXAMPLE H Al(acac)3

An aqueous solution of 4.0 wt % MPD, 4.5 wt % TEACSA and 0.2 wt % SLS inDI water was prepared. An Isopar G solution with 0.3 wt % TMC and 0.25%Al (acac)3 was also prepared and sonicated for 60 minutes.

A piece of wet polysulfone support was placed flat on a clean glassplate. An acrylic frame was then placed onto the membrane surface,leaving an area for the interfacial polymerization reaction to takeplace.

Aqueous MPD solution (50 mL) prepared as described previously was pouredonto the framed membrane surface and remained for 1 min. The solutionwas drained by tilting the frame till no solution dripped from theframe.

The frame was taken off, and was left horizontally for 4 minutes atwhich point most of the surface water had evaporated. The membrane wasthen clamped with the glass plate in four corners. An air knife was usedto finish drying of the membrane surface. The membrane was reframedusing another clean and dry acrylic frame and kept horizontally for 1min.

Organic solution (50 mL) was poured onto the framed membrane surface andremained for 2 min. The solution was drained by tilting the frame(vertically) till no solution dripped from the frame. The acrylic framewas removed, and the membrane was kept horizontally for 1 minute. Themembrane was then dried at 95 C for 6 minutes. A second membrane wasprepared as above, but the Isopar solution contained no Al(acac)3 so themembrane could serve as a control.

flux rejection control 9.9 99.3% Al(acac)3 20.2 99.7%

EXAMPLE I Al(acac)3 Tested on Pacific Ocean Seawater

A membrane made following the Al (acac)3 procedure above but using theAl (acac)3 at a level of 0.1%. The membrane was tested in flat cells onpretreated seawater taken from the Pacific Ocean.

flux rejection control 15.9 99.73% Al(acac)3 25.5 99.35%

EXAMPLE J Sodium Aluminate

An aqueous solution of 3.2 wt % MPD and 0.5% sodium aluminate, in DIwater was prepared. A Hexane solution with 0.17 wt % TMC was alsoprepared.

A piece of wet polysulfone support was placed flat on a clean glassplate. An acrylic frame was then placed onto the membrane surface,leaving an area for the IP reaction to take place.

Aqueous MPD solution (50 mL) prepared as described previously was pouredonto the framed membrane surface and remained for 1 minute. The solutionwas drained by tilting the frame till no solution dripped from theframe.

The frame was taken off, the membrane was then clamped with the glassplate in four corners. An air knife was used to meter and dry themembrane surface. The membrane was reframed using another clean and dryacrylic frame and kept horizontally for 1 minute.

Organic solution (50 mL) was poured onto the framed membrane surface andremained for 2 min. The solution was drained by tilting the frame(vertically) till no solution dripped from the frame. The acrylic framewas removed, and the membrane was kept horizontally for 1 minute.

A second membrane was prepared as above but the aqueous solutioncontained no sodium aluminate.

flux rejection control 20.0 98.99% sodium aluminate 30.6 96.77%

EXAMPLE K Aluminum Citrate

To the amine in the sodium aluminate example above, citric acid wasadded to bring the pH to the range of 7.5-9. The control did not requireany acid addition.

flux rejection control 18.2 98.78% Aluminum citrate 26.3 98.30%

EXAMPLE L Aluminum Camphorsulfonate

To the amine in the sodium aluminate example above, camphorsulfonic acidwas added to bring the pH to the range of 7.5-9. The insolubleprecipitate that formed was filtered before use. The control did notrequire any acid addition.

flux rejection control 18.2 98.78% aluminum camphorsulfonate 25.9 98.80%

EXAMPLE M AlCl₃

An aqueous solution of 3.2 wt % MPD in DI water was prepared. A Hexanesolution with 0.17 wt % TMC and 0.3% AlCl3 was also prepared andsonicated for 60 minutes.

A piece of wet polysulfone support was placed flat on a clean glassplate. An acrylic frame was then placed onto the membrane surface,leaving an area for the IP reaction to take place.

A 50 mL of aqueous MPD solution prepared as described previously waspoured onto the framed membrane surface and remained for 1 minute. Thesolution was drained by tilting the frame till no solution dripped fromthe frame.

The frame was taken off, the membrane was then clamped with the glassplate in four corners. An air knife was used to meter and dry themembrane surface. The membrane was reframed using another clean and dryacrylic frame and kept horizontally for 1 minute.

Organic solution (50 mL) was poured onto the framed membrane surface andremained for 2 minutes. The solution was drained by tilting the framevertically till no solution dripped from the frame. The acrylic framewas removed, and the membrane was kept horizontally for 1 minute.

A second membrane was prepared as above but the hexane solutioncontained no AlCl₃.

flux rejection control 14.0 99.47% AlCl3 16.1 99.60%

EXAMPLE N Effect of Rinsing

Two membranes were made following the Al (acac)3 procedure above butusing the Al (acac)3 at a level of 0.2%. One was then rinsed in a 0.2%sodium carbonate solution prior to testing.

flux rejection Al(acac)3 21.5 99.42% Al(acac)3, then sodium carbonaterinse 27.6 99.13%

EXAMPLE O Effect of Mixing Process

A membrane was made according to the Al(acac)3 example with the onlyexception being the organic solution was only sonicated for 10 minutes,a second membrane was made with the organic solution mechanicallystirred for 60 minutes. No sonication was used. A control was madewithout any Al(acac)3 present.

Flux Rejection control 17.6 99.6% stirring 21.2 99.5% sonication 27.799.2%

EXAMPLE P Contact Angle

Membranes were made according to the method of example H, and a secondmembrane was made without al(acac)3. The membrane contact angle with DIwater was then measured.

Contact angle Control 52.9 Al(acac)3 25.2

The soluble aluminum 17 released by nanoparticles 16 in support membrane12 are available in the water on the surface of membrane 12 which iskept wet until aqueous phase 14 is applied to support membrane 12 duringprocessing to prepare discrimination layer 24. As a result, soluble Al17 is available in aqueous phase 14 during interfacial polymerizationbetween organic and aqueous phases 18 and 14 to form discriminationlayer 24. The following examples are used to show the improved flux floware a result of the presence of soluble Al 17 in aqueous phase duringinterfacial polymerization which forms discrimination layer 24, referredto as Al or Al effect 19 in FIG. 3.

Example E shows the release of soluble aluminum from nanoparticles,while Example J shows the effect of soluble aluminum, in the aqueousphase during interfacial polymerization, on the flux and rejectioncharacteristics of a resultant membrane suitable for use in reverseosmosis.

EXAMPLE Q Release of Soluble Aluminum

Template-free zeolite LTA nanoparticles in an aqueous dispersion werefound to have aluminum content after being subjected to impact,cavitation and shear forces in a microfluidizer. The dispersioncontained approximately 39 weight percent LTA made with double distilledwater. When measured using ICP analysis, the solution had an aluminumcontent of 130.9 parts per million (ppm).

EXAMPLE R Commercial Scale Membrane Production

In a continuous coating process; the amine solution and a 0.075%Ga(acac)3 containing organic solution of example 2 were used to preparemembrane. Contact times for aqueous and organic solutions were about 15seconds. Other solutions and processing conditions were similar to thosein example 2.

flux rejection control 22.7 99.5% Ga(AcAc)₃ 43.0 98.7%

EXAMPLE S Effect of Impurity

Two membranes were prepared by the method in the aluminum citrateexample above, using two different lots of TMC. One was approximately99.5% pure, the other about 98.5% pure (purity from vendor) with traceamounts of mono, di-, and tri hydrolyzed TMC.

Control membranes with either TMC lot gave similar performance and wereaveraged for the “control” data below.

flux rejection control 18.3 98.85% 99.5% pure 20.5 98.75% 98.5% pure33.2 96.32%

Section B: Hybrid Membranes

Referring now generally to FIG. 18-26 and Tables I-X11 summarize ourdiscoveries that various combinations of additives and techniquesprovide substantially superior TFC membranes for forward and reverseosmosis for use, for example, in the purification of brackish andsaltwater. Such membranes have improved flux performance and foulingresistance and retain high rejection characteristics. In particular, inaddition to the advances in the use of nanoparticles and soluble metalions as additives noted above, there have been substantial advances madein the use of the following additives alone and in various combinationsand the following techniques alone and in combination, namely:

-   -   the use of nanoparticles in combination with various additives        to increase resistance to fouling and reduce the loss of flux        over time due to fouling,    -   the use of combinations of additives to increase flux without        substantial loss of rejection characteristics,    -   the use of mono-hydrolyzed TMC as an additive including the        monitoring of a deflection point,    -   the use of alkaline earth metals as additives,    -   the use of other molecular additives,    -   the use of nanotubes as additives,    -   the use of higher concentrations of TMC,    -   the use of lower ratios of MPD to TMC, as well as    -   the monitoring of the percent improvement of such additives and        combinations compared to control membranes.

Tables I-XII in Section C provide 172 additional examples of variousadditives used solely and in combination to identify points withinranges of the use of such additives and combinations, concentrations andranges.

In particular, as noted above, a combination of additives, such astemplate fee zeolite LTA nanoparticles, and metal ions, such as sodiumalum inate, in the aqueous phase of an interfacially polymerizedmembrane provide advantages not easily achievable if at all with singleadditives in similar membranes. Likewise, the use of zeolite LTAnanoparticles, combined with the use of a small amount of mono and/ordi-hydrolyzed TMC in the organic phase layer can have benefits notobserved with either used alone, due to interactions between thenanoparticles and mono and/or di-hydrolyzed TMC.

Still further, the use of alkaline earth metals and other molecularadditives, alone or combined with the other additives and/or with thetechniques, concentrations and ranges described provide hybrid TFCmembranes with high flux, high rejection and increased resistance tofouling. Although alkaline earth metals have not been used as additivesin RO membranes and were not expected to work, we surprisingly foundthat they could in fact work extremely well at increasing membranepermeability. Alkaline earth metals as a group are also abundant, lowcost, and easy to use in processing. Members of this group includingMagnesium, Calcium, and Strontium are also environmentally benign andcan be available as counter ions from zeolite nanoparticles. Mordeniteand Ferrierite are two example of zeolites with calcium or magnesiumexchangeable counterions.

Hybrid nanocomposite membranes can be thought of as a subclass of thinfilm composite or TFC membranes, where the polymer phase of thediscrimination layer both includes nanoparticles and has been modifiedthrough the use of one or more of these additives. Hybrid nanocompositeTFC membranes are interfacially prepared membranes formed in thepresence of nanoparticles, and/or one or more additives, and yielding amixed matrix membrane of the nanoparticles, and/or additives, togetherwith polymer, nanoparticles and additives, supported by an underlyinglayer, typically an ultra or microfiltration membrane.

The addition of a combination of nanoparticles, with other additives, toform hybrid nanocomposite TFC membranes may provide substantialincreased resistance to fouling, that is, to the loss of flux over timedue to contamination by the seawater or other material to be purified.

Other advantages of the various membrane additives and techniquesidentified so far are may include

-   -   substantial increased flux compared to the use of the membranes        with the individual additives,    -   substantial increased flux by the addition of small amounts of        mhTMC as an additive,    -   substantial flux and rejection performance by additives with        poor performance as single additives, and    -   substantial increased rejection for additives with poor        resection characteristics as single additives.

Fouling

With regard now in general to fouling, in some instances, hybridnanocomposite TFC membranes may be used to desalinate waters thatcontain materials which have a tendency to accumulate on the membranesurface in contact with the contaminated water, decreasing the effectivemembrane permeability, e.g. decreasing membrane flux over time. Thesematerials can include but are not limited to natural organic matter,partially insoluble inorganic materials, organic surfactants, silt,colloidal material, microbial species including biofilms, and organicmaterials either excreted or released from microbial species such asproteins, polysaccharides, nucleic acids, metabolites, and the like.This drop in permeability or membrane flux is often smaller formembranes prepared as disclosed herein than for membranes prepared byconventional techniques due to a decreased amount, density, viability,thickness and/or nature of accumulated material. Membrane surfaceproperties, such as hydrophilicity, charge, and roughness, often affectthis accumulation and permeability change. Generally, membranes withhighly hydrophilic, negatively charged, and smooth surfaces yield goodpermeability, rejection, and fouling behavior. The addition ofnanoparticles, such as zeolite LTA nanoparticles, have been shown toreduce roughness, increase negative charge without addition ofcarboxylate groups, and reduce contact angles.

Nanoparticles can also be added to increase membrane permeability whilemaintaining good rejection, and/or to improve the mechanical strength ofthe thin film or support layer.

Molecular additives have been used to alter the performance of purepolymer TFC membranes. However these improvements have often lead tomembranes having altered fouling propensity or decreased rejection,particularly when the membrane is used at high pressure and salinity,for instance during desalination of ocean water.

Hybrid membranes, that is, membranes with nanoparticles, and additivessuch as soluble ions, organometallic compounds, inorganic additives withor without ligands, and/or mhTMC enable a new degree of designflexibility to improve the overall flux, rejection, and foulingproperties of membranes. The several cases discussed below are meant toillustrate the range of benefits that can be realized through theapplication of hybrid membrane technology and are not meant to limit thescope of this application which is provided by the issued claims.

Some nanoparticles under specific processing conditions may have a largeeffect on membrane fouling, but have little or no effect, or at least aninsufficient impact, on membrane flux. In such cases, molecularadditives may be added to the membrane to provide an additional increasein flux while permitting the TFC membrane to retain the benefit of thefouling resistance provided, for example, by the nanoparticles.

Referring now in particular to Table IX. FOULING TEST, example 119 isbased on other experiments in which 0.1% of nanoparticles zeolite LTA,was added to the organic phase before interfacial polymerization or IFPwith an aqueous phase to produce a discrimination layer on a supportlayer and form a thin film nanocomposite or TFC membrane.

Membranes were prepared using the method of example 12. Membranes wererun on a feed solution of DI water with 32,000 ppm of a salt blendformulated to simulate natural ocean water (Instant Ocean®). Temperaturewas maintained at 25° C. and a pressure of 800 psi was used throughouttesting. No filtration was used during this test allowing inorganic andorganic colloids to recirculate through the system and biologicalmaterial to grow. Performance data was taken 1 hr after testing beganand again 47 hrs later after continuous operation.

The nanocomposite TFC membrane had 22.5 GFD flux rate, which is not animprovement over a control membrane made in the same manner but withoutthe nanoparticle additive, and had 98.5% salt rejection. The flux wasmaintained at 22.5 GFD by fouling after about two days.

Example 120 shows that a particular molecular additive Ga(acac)3,provided a reasonable total flux flow of 30.8 GFD, which provided a fluximprovement of about 36% over a control without additives and maintaineda very good salt rejection of over 99.5%. However, the Ga additivemembrane showed a poor flux performance after 47 hours of foulingtesting, losing almost half of its flux capacity.

Example 121 illustrates one of the benefits of a hybrid TFC membraneapproach in which nanoparticles, such as LTA are combined with molecularadditives, such as Ga(acac)3, to form an improved hybrid TFC membranewith qualities superior than are provided by either additive separately.In particular, the hybrid LTA Ga membrane provided 31.9 GFD flux, animprovement of about 41% more than the control with only slight loss insalt rejection. The further increase in flux is on the order of anaddition 14% when compared to the 36% flux increase of the Ga(acac)3additive. Perhaps even more importantly, the flux rate after the 47 hourtest was 27.3 GFD, i.e. the flux loss was only 17% after the 47 hourtest. As a result, the hybrid TFC membrane has substantially the fluximprovement of its soluble additive, in this case the Ga(acac)3, and thefouling resistance of the LTA nanoparticles.

Referring now to FIG. 25, a simple graphical representation of thereduced loss of flux over time is shown in which the LTA alone shows lowflux improvement with low flow loss due to fouling, the Ga additivealone shows high flux improvement with substantial flux loss due tofouling while the hybrid shows the best of both additives, high fluximprovement with low flux loss due to fouling. It should also be notedthat the TFC membrane with the additive alone has a lower flux than thenanocomposite TFC membrane while the nanocomposite hybrid TFC membraneshows a flux improvement over the nanoparticle hybrid TFC membrane ofabout 21% in only 2 days. The rate of flux drop tends to decrease inconventional membranes over time, but nanoparticle hybrid TFC membranesare expected to maintain an improvement of 20 to 100% above similarmembranes with single additives or conventional membranes.

Increased Flux

Regarding increased flux compared to membranes with the individualadditives, and referring now in particular to Tables II, IIA.2 andIIA.3, some nanoparticles and other additives may by themselves providea moderate increase in flux, when a larger response might be desired. Insuch cases, hybrid membrane technology can be used to produce membraneshaving the best overall performance.

Referring now to example 25, the use is illustrated of a concentrationof a particular nanoparticle, in this case a 0.05% concentration ofzeolite LTA, in the aqueous phase before contact with the organic phasefor interfacial polymerization to form a nanocomposite TFC membraneproviding 26.2 GFD at a 99.17% flux rejection. The flux rate provides a16% improvement over a control membrane made without the nanoparticle,which may be useful in some cases especially in light of the otherbenefits of nanoparticles. However, substantial further additional fluximprovement is often desired.

Referring now to example 30, the addition of a molecular additive, suchas a 0.058% concentration of Sr(f6(acac)2 in the organic phase, beforecontact with the aqueous phase, may produce a TFC membrane yielding a29.7 GFD flux rate, which at 31% has roughly double the 16% fluximprovement of example 25 in the table.

Referring now to example 2, a combination of the LTA and strontiumadditives may yield a hybrid nanocomposite TFC membrane with, at a 36.8GFD flux rate, a 63% improvement over a control membrane while providingan extremely good salt rejection of 99.57%.

mhTMC as an Additive

Referring now to FIGS. 18-21, monohydrolyzed TMC or mhTMC 16 may bedissolved as an additive, alone or in combination with another additivesuch as a nanoparticle or rare earth alkaline metal or other molecularadditive, in organic phase layer 18 before contact with aqueous layer 14during interfacial polymerization to increased flux and/or improverejection characteristics when TFC membrane 10 is used, for example,during reverse osmosis to purify saltwater 26.

Monohydrolyzed TMC 16 is a molecule of trimesoyl chloride or TMC inwhich one of the —Cl bonded groups has been replaced with a bonded OHgroup. Di-hydrolyzed trimesoyl chloride and tri-hydrolyzed trimesoylchloride (i.e., trimesic acid) often accompany monohydrolyzed TMC at lowlevels in TMC which has been hydrolyzed. Tri-hydrolyzed trimesoylchloride is believed to be a contaminant in that it appears to beinsoluble in organic phase 18 and may serve to increase flux in TFCmembrane 10 at the expense of rejection characteristics. Thecharacteristics of di-hydrolyzed trimesoyl chloride are not clearlyunderstood, but do not at this time appear to be substantiallybeneficial to the flux and rejection characteristics of TFC membraneswhich may explain why convention wisdom teaches the avoidance ofcontaminated TMC.

It may be beneficial, however, to have a small amount of mono-hydrolyzedTMC (1-carboxy-3,5-dichloroformylbenzene) and possibly somedi-hydrolyzed TMC (1,3-dicarboxy-5-chloroformylbenzene) present in theorganic phase layer 18 during the interfacial polymerization reaction.The ratio of mono and/or di-hydrolyzed TMC to TMC in the organic phaselayer 18 is preferably in the range of about 0.1/100 to 10/100 and morepreferably from 0.5/100 to 5/100. This impurity may interact with thenanoparticles and result in the formation of aligned channels and/orother mechanisms within the thin polymer film of discrimination membrane24 providing improved water flux.

To alter performance or solubility, a salt of monohydrolyzed TMC 16 maybe used in place of the acid form. Preferred salts may be those formedfrom substituted amines such as di, tri, or tetra methyl, ethyl, propyl,or butyl derivatives.

In addition to monohydrolyzed trimesoyl chloride or mhTMC, otherpartially hydrolyzed reactants may also be effective at improving flux.For example monohydrolyzed versions of 1,2,4 benzenetricarbonyltrichloride; 1,2,3-benzenetricarbonyl trichloride; and tricarbonylchloride substituted naphthalene, anthracene, phenanthrene, biphenyl, orother aromatic rings. Tricarbonyl chloride subsititued cycloaliphaticrings, or bicycloaliphatics are also included. Carbonyl chlorides ofhigher substitution than three may also be di or higher hydrolyzed, aslong as at least 2 carbonyl chloride groups remain allowingpolymerization to occur.

Monohydrolyzed TMC was synthesized for the examples described herein intwo lots, labeled lots 1 and 2 in Tables I-XII as will be discussedbelow in greater detail by the techniques described immediately below.Other monohydrolyzed polyhalides may be synthesized using similarmethods.

TMC was purified by reflux in thionyl chloride with DMF as catalyst.Impurities were pulled off under vacuum. The purified TMC was thendissolved in methylene chloride and reacted with Wang Resin (acommercially available solid phase polymer with reactive hydroxylgroups) at 0° C. Dilute triethylamine was added drop-wise over 2 hoursand the solution was then allowed to slowly warm up to room temperatureovernight. Excess reagents were rinsed away with excess methylenechloride. Cleavage with trifluoroacetic acid lead to isolation ofmonohydrolyzed TMC. Compound identity and purity was verified with1H-NMR of the isolated solid. NMR was run in deuterated toluene and isshown in FIG. 21 which identifies the presence of the synthesized mhTMC.

Preferred concentrations of the monohydrolyzed TMC 16 are from 0.005% to5% by weight and more preferred from 0.025% to 0.25% in organic layer18. The amount of monohydrolyzed TMC may also be compared in a ratiowith the amount of TMC. Preferred TMC/monohydrolyzed TMC ratios are lessthan 50:1, 25:1, 15:1, 5:1, or 1:1. From this it can be seen that athigh TMC concentrations more monohydrolyzed TMC may be needed to see acomparable flux increase. It may be beneficial to sonicate the solution.Sonication may serve to better disperse the monohydrolyzed TMC 16 inorganic solution 18. Sonication may also serve to drive reactions thatwould otherwise require higher temperatures, catalysts, or initiators tooccur. It may also be useful to use cosolvents to better solvate themonohydrolyzed TMC. Preferred cosolvents are those that are able to formclear solutions of the monohydrolyzed TMC before dilution. Particularlypreferred are aromatic solvents including benzene, toluene, xylene,mesitylene, or ethyl benzene. These cosolvents are preferably used atsufficiently low concentration to not negatively affect membraneperformance.

Referring now to FIGS. 19-20, mhTMC may be applied as an additive toorganic phase 18 before contact with aqueous phase 14 on porous support12 of RO membrane 10 during fabrication by interfacial polymerization toform discrimination layer of to TFC membrane 10. Other additives may beadded to the organic or aqueous phases or support or fabric layers 12 or20. Hydrophilic layer 30 may be applied to discrimination layer 24 sothat seawater 26 may be applied under pressure to TFC membrane 10 toproduce purified water 28.

The purity of the synthesized monohydrolyzed TMC may be estimated fromNMR spectra. Crude and purified monohydrolyzed TMC is dissolved indeuterated acetone for the NMR experiment. The purity calculation may beperformed by looking at the relative quantities of trimesic acid,1,3,5-Benzenetricarbonyl trichloride, monohydrolyzed TMC anddihydrolyzed 1,3,5-Benzenetricarbonyl trichloride. These values may thenbe reduced by any extraneous NMR peaks which usually impurities from thesynthesis.

Referring now again to FIG. 21, identity and purity of monohydrolyzedTMC can be verified through the use of H¹-NMR. After synthesis ofmonohydrolyzed TMC, the resultant product can be dissolved in deuteratedtoluene or deuterated acetone for this analysis. The doublet at 8.6 ppmcorresponds to the two aromatic ring protons adjacent to both a carbonylchloride and a carboxylic acid group. The integrated area of this peak,1.99, is twice that of the triplet at 8.4 ppm because there are twoprotons. The triplet at 8.4 ppm corresponds to the single aromatic ringproton between two carbonyl chloride groups. Purity of this compound canbe checked by comparing the integrated area of these protons versusthose of the non-hydrolyzed TMC, dihydrolyzed TMC, and trimesic acid.

Referring now to FIG. 26, membrane performance is illustratedgraphically as a function of the concentration of the mhTMC adjusted forpurity. In particular, the entries in Tables I-XII for mhTMC reflect theactual concentration of the synthesized mhTMC used identifying thesource of the mhTMC, i.e. synthesized lots 1 or 2. The graph lines inFIG. 26 have been adjusted for the estimated purity of the syntheziedmhTMC. The data for lots 1 and 2 have been adjusted for the estimatedconcentrations of synthesized mhTMC based on an NMR assay, includingsimple percentage of materials dissolvable in toluene. FIG. 26 providesa visual representation of the adjusted concentrations as functions ofGFD and Salt Rejection for lot 1 (80% pure mhTMC) and 2 (25% puremhTMC), as well as a separate plot line for a portion of lot 2 which hadbeen filtered to remove larger contaminants.

The filtering process substantially improved the salt rejection and onlyslightly reduced the flux. The remaining contamination seems to improvethe flux flow when it's at low values without much damage to rejection,but at the point of interest, at about 99.5% salt rejection, furthercontamination hurts the rejection at a much greater rate and only slightimproves flux. Another inflection point appears at about 0.020% or0.0215% where the flux climbs dramatically and the rejections dropsdramatically. This may indicate holes or tearing or some other degradingof the membrane. These regions of the chart may be characterized ascontamination-improved flux, contamination diminished-rejection, andcontamination-damaged zones.

In particular, the graph line for lot 1, adjusted to reflect that thesynthesized mhTMC of lot 1 was estimated to have about 80% concentrationof pure mhTMC, showed an increasing flux from 24 GFD at 0%concentration, i.e. at the control membrane concentration, to about 32.1GFD at about 0.0075% concentration adjusted at what appears to be adeflection point. The flux continued to grow, but at a slightly slowerrate until it reaches 39.7 GFD at the next data point at about 0.0215%adjusted mhTMC concentration and then dramatically increased to 45.1 GFDat 0.2050% adjusted concentration. The rejection characteristics of lot1 adjusted were very good at the 0% concentration of the controlmembrane at 99.8% rejection and had a similar deflection point at about99.60% rejection at about the 0.0075% adjusted mhTMC concentration ofthe deflection point. Thereafter, the rejection continued to decaythrough 99.11% at about 0.0150% adjusted concentration to 98.60% at0.02125% before it dropped to 96.20% at about 0.0250% concentration.

As a result, the addition of from 0% to perhaps 0.0150% adjustedconcentration provided very useful membrane performance, withconcentrations as high as about 0.02% to about 0.02125% being useful atsome conditions, but concentrations above that level suggest, togetherwith the dramatically increased flux, to indicate damage to themembrane. The optimal point appears to be in the neighborhood of thedeflection point at about 0.0075% adjusted mhTMC concentration, perhapsbetween 0.0050% and 0.01% adjusted concentration. The exact optimumpoint may have to be determined by experimentation.

Referring now to the graph line for lot 2, adjusted to reflect anestimated 25% concentration of pure mhTMC but not filtered, anincreasing flux was shown from the control membrane concentration of 0%mhTMC of 17.2 GFD growing dramatically to just under 30 GFD at about0.0050% adjusted concentration at which point the flux leveled off andreached only 31 GFD at about 0.0150% adjusted concentration. Thereafterit rose to about 37.5 GFD at 0.0250% adjusted concentration.

The flux characteristics of lot 2, adjusted and filtered, indicate thatthe flux grew reasonably linearly, from 17.2 GFD at 0% concentration,generally in parallel with the higher purity of the mhTMC from lot 1 to26.4 GFD at the deflection point of 0.0075% adjusted mhTMC concentrationand substantially joined the graph line of lot 2 unfiltered at about31.9 GFD at 0.0150% adjusted concentration. The fact that thecombination of the lot 2 adjusted and filtered flux growth linessubstantially join each other and run generally parallel with the fluxgrowth line for the higher purity samples for lot 1 indicate goodconsistency in the tests.

The rejection characteristics for lot 2, adjusted and filtered, showlittle degradation of rejection from the control membrane rejection at0% concentration of about 40 GFD to the same deflection point for lot 1at about 0.0075% adjusted concentration of mhTMC and follow lot 1 toabout 99.11% at about 0.0150% adjusted concentration. The consistencybetween the deflection point indications in both lots strongly indicatethat the deflection point in generally in the same range. Although thecommercially practical purity of the concentration of the mhTMCadditive, alone or together with other additives such as nanoparticles,alkaline earth metals or other molecular additives has not beendetermined, it is a matter of experimentation to determine theappropriate deflection point for optimal additive concentrations of themhTMC and other additives, and combinations of additives, in accordancewith the techniques as disclosed herein.

While not willing to be bound by theory, it is believed that the area tothe left of the vertical line at the concentration identified as thedeflection point, is the range of concentrations in which the additivesdisclosed herein promote increased flux while any remainingcontaminants—to the extent they effect the formation or structure of theinterfacially polymerized thin film discrimination layer of the TFCmembrane, serve to more or less increase the flux characteristics of theTFC membrane without substantially reducing the rejectioncharacteristics. This area has been designated for convenience as thecontaminate improved flux zone. After the deflection point, the effectof such contaminants has less beneficial effect on the growth of theflux but begins to have a substantial detriment to the rejectioncharacteristics of the membrane and has therefore been designated as thecontaminate reduced rejection zone. As the impact of the contaminantscontinues to increase with increasing concentration of the additive oradditives, a point will be reached, shown at 0.02125% adjustedconcentration, at which the contaminants increase the passage of bothpure water and materials to be rejected indicating damage or otherdetriment to membrane.

Without willing to be bound by theory, monohydrolyzed TMC 16 inparticular as an additive in organic phase 18 is believed to react withmetaphenylene diamine during the interfacial polymerization to improvethe hydrophilicity of the resultant polymer discrimination layer 24 toprovide additional benefits. It is thought that monohydrolyzed TMC 16may react with the polyfunctional nucleophilic monomer and may beincorporated into the polymeric discriminating layer 24 along withnon-hydrolyzed polyfunctional acyl halide. During polymerization thehydrolyzed acid group present on this reactant may interact withterminal charged amine residuals on the polyfunctional amine reactantforming ionic crosslinks. Such ionic crosslinks may increase thehydrophilicity of the polymer relative to a polymer containing amidecrosslinks exclusively, and thus promote increased water uptake andflux. At the same time rejection may be maintained by virtue of theelectrostatic interactions between the charged group, which isstabilized relative to normal electrostatic interactions, by therigidity of the crosslinked aromatic backbone keeping the two chargedcenters close to each other.

Referring now to one particular example of a hybrid nanocomposite TFCmembrane, as shown in example 8, the addition of 0.02% mono-hydrolyzedTMC, or mhTMC, has been shown to be extremely beneficial to the LTA,strontium hybrid TFC membrane described above. The resultant hybrid TFCmembrane including both strontium and mhTMC in the organic phase beforecontact with the aqueous phase during interfacial polymerization toproduce a discrimination layer which may deliver 42.4 GFD flux at a verygood 99.16% salt rejection rate. The flux improvement of 88%, from the22.6 GFD flux of the control membrane coupled with a very modest loss insalt rejection makes for a useful membrane for several applications.

Poor Performance as Single Additive

Regarding additives with poor performance as single additives, andreferring now again to Tables II, IIA.2 and IIA.3, some additives andnanoparticles do not provide an obvious or substantial improvement inperformance when used alone. However, combinations of nanoparticles andadditives have proven to be substantially useful by providing fluxincreases when incorporated into hybrid TFC membranes.

As shown in example 26, a 0.05% concentration of LTA to the Isopar basedorganic phase before contact during IFP with the aqueous phase yields ananocomposite TFC membrane with a 22.6 GFD flux, equal to that of thecontrol membrane, but a salt rejection of 98.77%, lower than the 99.68%of the control membrane.

As shown in example 29, a 0.09% Ca(f6acac)2 additive to the ISOPAR basedorganic phase yields a TFC membrane with 24.8 GFD flux having about a10% flux increase over the control membrane without additives, with agood salt rejection of 99.63%.

Referring now to examples 19, a membrane made with LTA and the Caadditive, in the ISOPAR based organic phase yields a nanocompositehybrid TFC membranes having 34.4 GFD flux having, a 52% flux increaseover the control membrane without additives but with good salt rejectionof 99.03%.

Regarding additives with poor decreased rejection and referring now toTable II, IIA.2 and X, additives can be used with some nanoparticlesthat may by themselves have acceptable flux increases but decreasedrejection, to produce hybrid TFC membranes can be made that have thesame or similar flux responses, but with improved rejection relative toeither additive alone.

Poor Rejection Characteristics as Single Additive

Referring now to example 25, a nanocomposite TFC membrane with 0.05% LTAadditive in the aqueous phase may yield a flux of 26.2 GFD, a 10% fluximprovement over a control membrane without nanoparticle as well as a99.17% salt rejection, below the 99.68% rejection of the controlmembrane

Referring now to example 129, a TFC membrane with 0.02% mhTMC additivein the organic phase may yield a flux of 29.5 GFD having a 31% fluximprovement over a control membrane without additives as well as a99.24% salt rejection, also below the rejection of the control membrane.

Referring now to example 21, a hybrid TFC membrane with both the LTA andmhTMC additives may yield a flux of 30.7 GFD, yielding a better fluximprovement of 36% and, perhaps more importantly, a substantiallyimproved salt rejection of 99.63%, much closer to the 99.68% saltrejection of the control membrane.

Section C Concentration of TMC

An analysis of the concentration of TMC used in organic phase 18indicates that a minimum concentration may be required to get the fullbenefit of the additive(s) described herein. As shown in Tables I-XII,concentrations of TMC less than about 0.17% or 0.2% TMC or greater thanabout 0.5% TMC were not optimal to get the beneficial effects of many ofthe additives. The preferred range is therefore about 0.15% to about0.6%, more preferred from 0.2% to 0.5% and most preferred from about0.25% to 0.33%.

Ratio of MPD to TMC

The ratio of MPD to TMC may be another important factor in thepreparation of high flux, high rejection, low fouling TFC membranes,particularly with the additives and combinations of additives describedherein. The preferred range is less than a ratio of about 35 for use inconjunction with the TMC concentrations discussed above, more preferablyless than 25 and even more preferably less than about 15. A mostpreferred ratio is about 13.

Nanotubes

When nanotubes 16 are included in the aqueous phase it may be preferableto include surfactants such as; Alkyl poly(ethylene oxide), Copolymersof poly(ethylene oxide) and poly(propylene oxide) (commercially calledPoloxamers or Poloxamines), Alkyl polyglucosides including Octylglucoside or Decyl maltoside, Fatty alcohols including Cetyl alcohol orOleyl alcohol, Cocamide MEA, or cocamide DEA, to help disperse thenanotubes. These may also be chosen so as to help align nanotubes 16 ina specific arrangement. It will be obvious to one skilled in the art touse other nonionic, cationic, anionic, or zwitterionic surfactants toaid in dispersing or aligning the nanoparticles.

Nanoparticles such as tubes 16 may be carbon nanotubes, may be made ofFeC, titania, WS2, MoS2, Boron Nitride, Silicon, Cu, Bi, ZnO, GaN,In2O3, Vanadium oxide, or Manganese oxide. When carbon nanotubes 16 areused they may be single or multiwall, and may have a functionalizedsurface including derivitization with alcohol or carboxylic acid groups.Nanotube length may be from 100 nm up to 50 microns, more preferably 100nm to 2 microns, and more preferably 0.5 microns to 2 microns. Nanotubediameter may be less than 50 nm, preferably less than 25 nm and morepreferably from 1-2 nm. Nanotubes 16 may be thoroughly rinsed, or usedas is. When used as is, trace impurities may be present includingunreacted carbon precursors or carbon in other phases, oxidizedmaterials, nanotube synthesis materials such as cobolt containingcompounds, and other impurities. Nanotubes 16 may also be processedbefore use to make them more beneficial for use in thin filmnanocomposite membranes. For instance laser ablation or treatment with astrong acid can be used to shorten the average length of the nanotubes.Ultra-high pressure homogenization, for instance by a Microfluidizer®may be used to break up nanoparticle bundles and to shorten averagenanoparticle length.

In some instances it may be preferred to align nanotubes 16 within themembrane. For example in some instances it may preferred to alignnanotubes 16 normal to the superficial membrane surface. This can beused for example in situations where transport occurs through theinterior of the nanotube and the smallest length of nanotube is desiredto minimize resistance to transport. This can be accomplished byutilizing a magnetic catalyst that is incorporated with at least someand preferably a plurality of each of the nanotubes of nanotubes 16. Inthis case a magnetic field may be used during the interfacialpolymerization to then trap nanotubes 16 in this configuration. In asimilar manner, surfactants may be used to align nanotubes 16,particularly when used in the aqueous phase. Suitable surfactantsinclude; Alkyl poly(ethylene oxide), Copolymers of poly(ethylene oxide)and poly(propylene oxide) (commercially called Poloxamers orPoloxamines), Alkyl polyglucosides including Octyl glucoside or Decylmaltoside, Fatty alcohols including Cetyl alcohol or Oleyl alcohol,Cocamide MEA, or cocamide DEA. It may also be possible to use othernonionic, cationic, anionic, or zwitterionic surfactants to aid inaligning the nanoparticles.

In other instances the preferred alignment may be in the plane ofmembrane 10. This allows much longer nanotubes 16 to be used that canimpart improved mechanical properties to thin film nanocompositemembrane 10. To accomplish this, shear may be applied to the coatingsolution, for instance by application of the amine or organic solutionby a slot die coating method, or a dip coating process. Nanotubes 16 maybe aligned by this method in either the aqueous or organic solution.

Nanocomposite TFC membranes 10 containing nanotubes 16 can also havesurprising biocidal activity. It appears that in some instances thatpartially exposed nanotubes 16 may be able to pierce, or cut the cellwall of microorganisms leading to cell death. In this way the membranesurface exhibits antimicrobial activity.

An aqueous solution of 4.0 wt % MPD, 4.5 wt % TEACSA and 0.06 wt % SLSin DI water was prepared. An Isopar G solution with 0.3 wt % TMC and0.1% carbon nanotubes 16 (0.5-2 micron long single wall) was alsoprepared and sonicated for 60 minutes. The membrane was prepared asdescribed above. The membrane was then dried at 95 C for 6 minutes.Performance is shown in example 44.

Average Flux (gfd) Average Rejection (%) Control 22.1 (2.5) 99.66 (0.11)0.1% Carbon Nanotubes 28.5 (1.8) 99.64 (0.08)

Section D: Tables I-XII, Examples 1-172

MPD/TMC ORG % FLUX Ex.# MPD TMC RATIO AQ NP ORG NP ADDITIVE IMPROVEMENTFLUX REJ. I. CONTROL MEMBRANE (NO ADDITIVES)   1 4% 0.30% 13.3 22.699.68% MPD TMC GFD II. HYBRID MEMBRANES WITH LTA NP/ALKALINE EARTHADDITIVES/mhTMC   2 4% 0.30% 13.3 0.05% LTA 0.058% 63% 36.8 99.57% MPDTMC Sr(f6acac)2 GFD   3 4% 0.30% 13.3 0.1% LTA 0.116% 87% 42.3 98.44%MPD TMC Sr(f6acac)2 GFD   4 3% 0.20% 15.0 0.1% LTA 0.116% 40.7 99.20%MPD TMC Sr(f6acac)2 GFD   5 3% 0.40% 7.5 0.1% LTA 0.116% 39.3 99.12% MPDTMC Sr(f6acac)2 GFD   6 5% 0.20% 25.0 0.1% LTA 0.116% 40.3 99.41% MPDTMC Sr(f6acac)2 GFD   7 5% 0.40% 12.5 0.1% LTA 0.116% 31.3 99.27% MPDTMC Sr(f6acac)2 GFD   8 4% 0.30% 13.3 0.05% LTA 0.06% Sr(f6acac)2 88%42.4 99.16% MPD TMC 0.02% mhTMC lot 2 GFD   9 4% 0.30% 13.3 0.05% LTA0.058% 57% 35.5 99.48% MPD TMC Sr(f6acac)2 GFD  10 4% 0.30% 13.3 0.1%LTA 0.116% 77% 40 98.63% MPD TMC Sr(f6acac)2 GFD  11 3% 0.40% 7.5 0.1%LTA 0.116% 29.5 98.61% MPD TMC Sr(f6acac)2 GFD  12 5% 0.40% 12.5 0.1%LTA 0.116% 30.3 99.15% MPD TMC Sr(f6acac)2 GFD  13 4% 0.30% 13.3 0.05%LTA 0.06% Sr(f6acac)2 25% 28.2 98.81% MPD TMC 0.02% mhTMC lot 2 GFD  144% 0.30% 13.3 0.05% LTA 0.09% Ca(F6acac)2 69% 38.1 99.31% MPD TMC 0.02%mhTMC lot 2 GFD  15 4% 0.30% 13.3 0.05% LTA 0.09% Ca(F6acac)2 52% 34.495.11% MPD TMC 0.02% mhTMC lot 2 GFD  16 4% 0.30% 13.3 0.05%LTA 0.09%Ca(F6acac)2 1% 22.9 99.53% MPD TMC GFD  17 4% 0.30% 13.3 0.05% LTA 0.44%27% 28.7 99.71% MPD TMC Mg(F6acac)2 GFD  18 4% 0.30% 13.3 0.05% LTA0.11% 2% 23.0 99.60% MPD TMC Ca(acac)2 GFD  19 4% 0.30% 13.3 0.05% LTA0.09% 52% 34.4 99.02% MPD TMC Ca(F6acac)2 GFD  20 4% 0.30% 13.3 0.05%LTA 0.02% 8% 24.3 99.50% MPD TMC Be(acac)2 GFD IIA.1 WITH LTA NP ANDmhTMC  21 4% 0.30% 13.3 0.05% LTA 0.02% mhTMC lot 2 36% 30.7 99.63% MPDTMC GFD  22 4% 0.30% 13.3 0.05% LTA 0.02% mhTMC lot 2 14% 25.8 99.63%MPD TMC GFD IIA.2 WITH LTA NP ONLY  23 2.75% 0.09% 30.6 0.05% LTA 30.299.48% MPD TMC GFD  24 2.75% 0.09% 30.6 0.1% LTA 29.7 97.29% MPD TMC GFD 25 4% 0.30% 13.3 0.05% LTA 16% 26.2 99.17% MPD TMC GFD  26 4% 0.30%13.3 0.05% LTA 0% 22.6 98.77% MPD TMC GFD  27 2.75% 0.09% 30.6 0.05% LTA30.1 99.56% MPD TMC GFD  28 2.75% 0.09% 30.6 0.1% LTA 28.5 99.62% MPDTMC GFD IIA.3 WITH ALKALINE EARTH ADDITIVES ONLY  29 4% 0.30% 13.3 0.09%10% 24.8 99.63% MPD TMC Ca(F6acac)2 GFD  30 4% 0.30% 13.3 0.058% 31%29.7 99.57% MPD TMC Sr(f6acac)2 GFD  31 4% 0.30% 13.3 0.02% mhTMC lot 231% 29.5 99.24% MPD TMC GFD  32 4% 0.30% 13.3 0.44% 24% 28.0 99.6% MPDTMC Mg(f6acac)2 GFD  33 4% 0.30% 13.3 0.11% 23% 27.9 99.58% MPD TMCCa(acac)2 GFD  34 4% 0.30% 13.3 0.048% 29% 29.2 99.49% MPD MC Be(acac)2GFD III. HYBRID EXEMPLAR with CuMOF NP & ALKALINE EARTH ADDITIVES  35 4%0.30% 13.3 0.05% 0.058% 51% 34.2 99.53% MPD TMC Cu MOF Sr(f6acac)2 GFDIII.A EXEMPLAR WITH Cu MOF NP ONLY  36 4% 0.30% 13.3 0.05% 8% 24.399.71% MPD TMC Cu MOF GFD IV. HYBRID EXEMPLAR with SiO2 NP & ALKALINEEARTH ADDITIVES  37 4% 0.30% 13.3 0.05% 0.058% 62% 36.6 98.66% MPD TMCSiO2 Sr(f6acac)2 GFD IV.A EXEMPLAR WITH Si02 NP ONLY  38 4% 0.30% 13.30.05% −1% 22.3 99.57% MPD TMC SiO2 GFD V. HYBRID EXEMPLAR with ZEOLITEBETA NP & ALKALINE EARTH ADDITIVES  39 4% 0.30% 13.3 0.05% 0.058% 33% 3099.61% MPD TMC BETA Sr(f6acac)2 GFD V.A EXEMPLAR WITH ZEOUTE BETA NPONLY  40 4% 0.30% 13.3 0.05% 0% 22.7 99.51% MPD TMC BETA GFD VI. HYBRIDEXEMPLAR with CARBON NANOTUBE NP & ALKALINE EARTH ADDITIVES  41 4% 0.30%13.3 0.05% 0.058% 72% 38.76 98.83% MPD TMC NANOTUBE Sr(f6acac)2 GFD  424% 0.30% 13.3 0.05% 0.04% 39% 31.5 99.62% MPD TMC NANOTUBE Ga(acac)3 GFD 43 4% 0.30% 13.3 0.05% 0.06% mhTMC 62% 36.5 97.37% MPD TMC NANOTUBE GFDVI.A EXEMPLAR WITH CARBON NANOTUBE NP ONLY  44 4% 0.30% 13.3 0.1% 26%28.5 99.64% MPD TMC NANOTUBE GFD VII. HYBRID EXEMPLAR with ZEOLITE FAUNP & ALKALINE EARTH ADDITIVES  45 4% 0.30% 13.3 0.05% FAU 0.058% 47%33.2 99.42% MPD TMC Sr(f6acac)2 GFD VIII. HYBRID MEMBRANES WITHLTA/ADDITIVE/mhTMC  46 4% 0.30% 13.3 0.05% LTA 0.04% Al(acac)3 56% 35.399.44% MPD TMC GFD  47 4% 0.30% 13.3 0.1% LTA 0.08% Al(acac)3 63% 36.898.81% MPD TMC GFD  48 3% 0.20% 15.0 0.1% LTA 0.08% Al(acac)3 48.698.37% MPD TMC GFD  49 3% 0.40% 7.5 0.1% LTA 0.08% Al(acac)3 44.9 98.69%MPD TMC GFD  50 5% 0.40% 12.5 0.1% LTA 0.08% Al(acac)3 35.5 99.13% MPDTMC GFD  51 4% 0.30% 13.3 0.05% 0.04% Al(acac)3 48% 33.4 99.54% MPD TMCLTA GFD  52 4% 0.30% 13.3 0.1% 0.08% Al(acac)3 67% 37.7 99.32% MPD TMCLTA GFD  53 3% 0.20% 15.0 0.1% 0.08% Al(acac)3 40.1 99.22% MPD TMC LTAGFD  54 3% 0.40% 7.5 0.1% 0.08% Al(acac)3 41.6 98.61% MPD TMC LTA GFD 55 5% 0.20% 25.0 0.1% 0.08% Al(acac)3 37.2 99.30% MPD TMC LTA GFD  565% 0.40% 12.5 0.1% 0.08% Al(acac)3 29.3 99.32% MPD TMC LTA GFD  57 4%0.30% 13.3 0.05% LTA 0.04% Al(acac)3 41% 31.8 99.51% MPD TMC 0.02% mhTMClot 2 GFD  58 4% 0.30% 13.3 0.05% 0.04% Al(acac)3 35% 30.4 99.58% MPDTMC LTA 0.02% mhTMC lot 2 GFD  59 4% 0.30% 13.3 0.1% 0.08% Ga(acac)3 50%33.8 99.54% MPD TMC LTA GFD  60 4% 0.30% 13.3 0.05% LTA 0.03% 19% 26.999.60% MPD TMC Tributylphosphate GFD  61 4% 0.30% 13.3 0.05% LTA 0.03%85% 41.7 99.27% MPD TMC Triphenylphosphine GFD  62 4% 0.30% 13.3 0.05%LTA 0.04% Pd(acac)2 4% 23.5 99.55% MPD TMC GFD  63 4% 0.30% 13.3 0.05%LTA 0.07% Hf(acac)4 3% 23.3 99.44% MPD TMC GFD  64 4% 0.30% 13.3 0.05%LTA 0.139% % 2% 23.1 99.35% MPD TMC Nd(f6acac)3 GFD  65 4% 0.30% 13.30.05% LTA 0.029% Na(acac) −1% 22.4 99.52% MPD TMC GFD  66 4% 0.30% 13.30.05% LTA 0.06% Yb(acac)3 −4% 21.8 99.50% MPD TMC GFD  67 4% 0.30% 13.30.05% LTA 0.06% Er(acac)3 9% 24.6 99.53% MPD TMC GFD  68 4% 0.30% 13.30.05% LTA 0.03% Zn(acac)2 4% 23.4 99.58% MPD TMC GFD  69 4% 0.30% 13.30.05% LTA 0.034% K(acac) 6% 24.0 99.66% MPD TMC GFD  70 4% 0.30% 13.30.05% LTA 0.024% % Li(acac) 4% 23.5 99.63% MPD TMC GFD  71 4% 0.30% 1330.05% LTA 0.107% % Dy(acac)3 −9% 20.6 99.46% MPD TMC GFD  72 4% 0.30%13.3 0.05% LTA 0.113% Tb(acac)3 −4% 21.6 99.51% MPD TMC GFD  73 4% 0.30%13.3 0.05% LTA 0.1% Zr(acac)4 11% 25.0 99.51% MPD TMC GFD  74 4% 0.30%13.3 0.05% LTA 0.087% % Ni(acac)2 −4% 21.8 99.53% MPD TMC GFD  75 4%0.30% 13.3 0.05% LTA 0.111% % Sm(acac)3 2% 23.0 99.60% MPD TMC GFD  764% 0.30% 13.3 0.05% LTA 0.092% Mn(acac)3 21% 27.4 99.43% MPD TMC GFD  774% 0.30% 13.3 0.05% LTA 0.093% Mn(acac)2 6% 24.0 99.61% MPD TMC GFD  784% 0.30% 13.3 0.05% LTA 0.04% Fe(acac)3 31% 29.7 99.57% MPD TMC GFD  794% 0.30% 13.3 0.05% LTA 0.05% Sn(bu)2(acac)2 71% 38.7 98.87% MPD TMC GFD 80 4% 0.30% 13.3 0.05% LTA 0.04% Cu(f6acac)2 41% 32.0 99.24% MPD TMCGFD  81 4% 0.30% 13.3 0.05% LTA 0.04% Co(acac)3 12% 25.2 99.50% MPD TMCGFD  82 4% 0.30% 13.3 0.05% LTA 0.09% Pr(f6acac)3 91% 43.3 98.38% MPDTMC GFD  83 4% 0.30% 13.3 0.05% LTA 0.06% Zn(f6acac)2 16% 26.3 99.61%MPD TMC GFD  84 4% 0.30% 13.3 0.05% LTA 0.04% Cr(acac)3 23% 27.8 99.60%MPD TMC GFD  85 4% 0.30% 13.3 0.05% LTA 0.05% In(acac)3 16% 26.3 99.37%MPD TMC GFD  86 4% 0.30% 13.3 0.05% LTA 0.05% V(acac)3 26% 28.4 99.54%MPD TMC GFD  87 4% 0.30% 13.3 0.05% LTA 0.04% Sn(acac)2Cl2 8% 24.599.61% MPD TMC GFD  88 4% 0.30% 13.3 0.05% LTA 0.05% Ru(acac)3 24% 28.099.65% MPD TMC GFD  89 4% 0.30% 13.3 0.05% LTA 0.038% MoO2(acac)2 2%23.0 99.51% MPD TMC GFD  90 4% 0.30% 13.3 0.05% LTA 0.03% Cu(acac)2 9%24.6 99.39% MPD TMC GFD  91 4% 0.30% 13.3 0.05% LTA 0.03% Sn(t-bu)2Cl25% 23.8 99.54% MPD TMC GFD  92 4% 0.30% 13.3 0.05% LTA 0.04% Cd(acac)21% 22.9 99.58% MPD TMC GFD  93 4% 0.30% 13.3 0.05% LTA 0.172%%Y(f6acac)3 8% 24.4 97.28% MPD TMC GFD VIIIB. EXEMPLARS WITH AdditivesONLY  94 4% 0.30% 13.3 0.04% Al(acac)3 34% 30.2 99.38% MPD TMC GFD  954% 0.30% 13.3 0.084% Fe(acac)3 90% 42.9 98.70% MPD TMC GFD  96 4% 0.30%13.3 0.1% Sn(bu)2(acac)2 117% 49.1 97.81% MPD TMC GFD  97 4% 0.30% 13.30.085% Cu(f6acac)2 83% 41.3 98.98% MPD TMC GFD  98 4% 0.30% 13.3 0.086%Co(acac)3 47% 33.2 99.62% MPD TMC GFD  99 4% 0.30% 13.3 0.18%Pr(f6acac)3 46% 33 99.28% MPD TMC GFD 100 4% 0.30% 13.3 0.12%Zn(f6acac)2 44% 32.6 99.63% MPD TMC GFD 101 4% 0.30% 13.3 0.086%Cr(acac)3 37% 31 99.64% MPD TMC GED 102 4% 0.30% 13.3 0.1% In(acac)3 38%31.2 99.30% MPD TMC GFD 103 4% 0.30% 13.3 0.1% V(acac)3 28% 28.9 99.60%MPD TMC GFD 104 4% 0.30% 13.3 0.086% Sn(acac)2Cl2 27% 28.8 99.46% MPDTMC GFD 105 4% 0.30% 13.3 0.092% Ru(acac)3 23% 27.8 99.72% MPD TMC GFD106 4% 0.30% 13.3 0.076% MoO2(acac)2 31% 29.5 99.53% MPD TMC GFD 107 4%0.30% 13.3 0.06% Cu(acac)2 19% 26.8 99.48% MPD TMC GFD 108 4% 0.30% 13.30.065% Sn(t-bu)2Cl2 17% 26.5 99.07% MPD TMC GFD 109 4% 0.30% 13.3 0.072%Cd(acac)2 15% 26 99.70% MPD TMC GFD 110 4% 0.30% 13.3 0.077% Pd(acac)215% 25.9 99.66% MPD TMC GFD 111 4% 0.30% 13.3 0.013% Hf(acac)4 12% 25.499.55% MPD TMC GFD 112 4% 0.30% 13.3 0.13% Nd(f6acac)3 11% 25 99.60% MPDTMC GFD 113 4% 0.30% 13.3 0.029% Na(acac) 11% 25 99.44% MPD TMC GFD 1144% 0.30% 13.3 0.11% Yb(acac)3 9% 24.6 99.52% MPD TMC GFD 115 4% 0.30%13.3 0.11% Er(acac)3 5% 23.7 99.62% MPD TMC GFD 116 4% 0.30% 13.3 0.065%Zn(acac)2 4% 23.6 99.48% MPD TMC GFD 117 4% 0.30% 13.3 0.034% K(acac) 0%22.6 99.44% MPD TMC GFD 118 4% 0.30% 13.3 0.024% Li(acac) −1% 22.399.54% MPD TMC GFD MPD/TMC ORG FLUX at Flux at Ex. # MPD TMC RATIO ORGNP ADDITIVE 1 hr 47 hrs REJ. IX. FOULING TEST 119 4% 0.30% 13.3 0.1% LTA22.5 22.5 98.50% MPD TMC GFD GFD 120 4% 0.30% 13.3 0.08% Ga(acac)3 30.820.9 99.53% MPD TMC GFD GFD 121 4% 0.30% 13.3 0.1% LTA 0.08% Ga(acac)331.9 27.3% 99.42% MPD TMC GFD GFD MPD/TMC ORG ORGANIC EX. # MPD TMCRATIO ADDITIVE FILTERED FLUX REJ. X. IMPROVEMENTS WITH mhTMC IN TFCMEMBRANES 122 4% 0.30% 13.3 0% mhTMC lot 1 NO 24 99.70% MPD TMC GFD 1234% 0.30% 13.3 0.0094% mhTMC lot 1 NO 32.1 99.60% MPD TMC GFD 124 4%0.30% 13.3 0.028% mhTMC lot 1 NO 39.7 98.60% MPD TMC GFD 125 4% 0.30%13.3 0.031% mhTMC lot 1 NO 45.1 96.20% MPD TMC GFD 126 4% 0.30% 13.3 0%mhTMC lot 2 NO 17.2 99.62% MPD TMC GFD 127 4% 0.30% 13.3 0.005% mhTMClot 2 NO 20.5 99.54% MPD TMC GFD 128 4% 0.30% 13.3 0.01% mhTMC lot 2 NO25.8 99.45% MPD TMC GFD 129 4% 0.30% 13.3 0.02% mhTMC lot 2 NO 29.599.24% MPD TMC GFD 130 4% 0.30% 13.3 0.03% mhTMC lot 2 NO 29.6 99.05%MPD TMC GFD 131 4% 0.30% 13.3 0.04% mhTMC lot 2 NO 30.8 98.18% MPD TMCGFD 132 4% 0.30% 13.3 0.05% mhTMC lot 2 NO 31.1 97.69% MPD TMC GFD 1334% 0.30% 13.3 0.06% mhTMC lot 2 NO 31.2 96.07% MPD TMC GFD 134 4% 0.30%13.3 0.1% mhTMC lot 2 NO 37.4 92.25% MPD TMC GFD 135 4% 0.30% 13.3 0.03%mhTMC lot 2 YES 26.4 99.56% MPD TMC GFD 136 4% 0.30% 13.3 0.06% mhTMC bt2 YES 31.9 99.11% MPD TMC GFD MPD/TMC ORG ORG % FLUX Ex. # MPD TMC RATIONP ADDITIVE INCREASE FLUX REJ. XI. EFFECT OF TMC CONCENTRATION ONADDITIVE FLUX INCREASE 137 4% 0.30% 13.33 0.1% Al(acac)3 31 99.05% MPDTMC GFD 138 4% 0.30% 13.33 0.062% 31.8 99.37% MPD TMC TributylphosphateGFD 139 4% 0.30% 13.33 0.08% Ga(acac)3 32 99.64% MPD TMC GFD 140 4%0.30% 13.33 0.116% Sr(f6acac)2 32.2 99.38% MPD TMC GFD 141 3.2% 0.17%18.82 0.1% Al(acac)3 76% 98.33% MPD TMC 142 3.2% 0.30% 10.67 0.1%Al(acac)3 80% 98.86% MPD TMC 143 4% 0.17% 23.53 0.1% Al(acac)3 29%95.23% MPD TMC 144 4% 0.30% 13.33 0.1% Al(acac)3 102% 99.05% MPD TMC 1452.5% 0.09% 27.78 0.062% 10% 99.32% MPD TMC Tributylphosphate 146 2.5%0.30% 8.33 0.062% 48% 99.19% MPD TMC Tributylphosphate 147 2.5% 0.50%5.00 0.062% 85% 98.92% MPD TMC Tributylphosphate 148 4% 0.09% 44.440.082% −28% 91.64% MPD TMC Tributylphosphate 149 4% 0.30% 13.33 0.062%44% 99.37% MPD TMC Tributylphosphate 150 4% 0.50% 8.00 0.062% 44% 99.00%MPD TMC Tributylphosphate 151 2.5% 0.10% 25.00 0.08% 20% 99.00% MPD TMCGa(acac)3 152 2.5% 0.20% 12.50 0.08% 31% 99.11% MPD TMC Ga(acac)3 1532.5% 0.30% 8.33 0.08% 42% 99.48% MPD TMC Ga(acac)3 154 2.5% 0.40% 6.250.08% 34% 99.32% MPD TMC Ga(acac)3 155 2.5% 0.50% 5.00 0.08% 23% 99.22%MPD TMC Ga(acac)3 156 4% 0.10% 40.00 0.08% 29% 24.05% MPD TMC Ga(acac)3157 4% 0.20% 20.00 0.08% 34% 99.37% MPD TMC Ga(acac)3 158 4% 0.30% 13.330.08% 28% 99.64% MPD TMC Ga(acac)3 159 4% 0.40% 10.00 0.08% 42% 99.50%MPD TMC Ga(acac)3 160 4% 0.50% 8.00 0.08% 57% 99.55% MPD TMC Ga(acac)3161 2.5% 0.09% 27.78 0.116% 1% 99.25% MPD TMC Sr(f6acac)2 162 2.5% 0.30%8.33 0.116% 53% 99.21% MPD TMC Sr(f6acac)2 163 2.5% 0.50% 5.00 0.116%46% 99.11% MPD TMC Sr(f6acac)2 164 4% 0.09% 44.44 0.116% 13% 23.38% MPDTMC Sr(f6acac)2 165 4% 0.30% 13.33 0.116% 46% 99.38% MPD TMC Sr(f6acac)2166 4% 0.50% 8.00 0.116% 34% 99.11% MPD TMC Sr(f6acac)2 XII. EFFECT OFTMC CONCENTRATION ON ADDITIVE FLUX INCREASE 167 6% 0.20% 30.00 0.05% 55%37.6 98.73% MPD TMC Al(acac)3 GFD 168 6% 0.30% 20.00 0.05% 43% 34.898.43% MPD TMC Ga(acac)3 GFD 169 6% 0.30% 20.00 0.05% 41% 34.2 99.47%MPD TMC Fe(acac)3 GFD 170 6% 0.30% 20.00 0.08% 13% 27.5 98.21% MPD TMCCr(acac)3 GFD 171 6% 0.30% 20.00 0.06% 24% 30.1 99.51% MPD TMCTributylphosphate GFD 172 6% 0.30% 20.00 0.06% 32% 32 97.45% MPD TMCTriphenylphosphine GFD

Section E. Preparation and Testing Methodology for the Example MembranesFouling Example

Description of Nanoparticles Used

-   -   LTA: Linde Type A zeolite from Nanoscape. 100 nm Diameter freeze        dried.    -   SiO2: Ludox silica

-   Cu MOF: A metal organic framework complex prepared from Cu and    trimesic acid as described in Science 283, 1148 (1999); Stephen    S.-Y. Chui, et al. “[Cu3(TMA)2(H2O)3]n A Chemically Functionalizable    Nanoporous Material”    -   FAU: Linde type Y zeolite as described in MICROPOROUS AND        MESOPOROUS MATERIALS Volume: 59 Issue: 1 Pages: 13-28 Published:        Apr. 18, 2003 by Holmberg B A, Wang H T, Norbeck J M, Yan Y S    -   Beta: Zeolite Beta as described in MICROPOROUS AND MESOPOROUS        MATERIALS Volume: 25 Issue: 1-3 Pages: 59-74 Published: Dec. 9,        1998 by Camblor M A, Corma A, Valencia S

Aqueous Phase Nanoparticles. Example 2-8, 16-18, 20, 21, 23-25, 37-40,45-50, 57, 60-93

To an aqueous dispersion of nanoparticles was added MPD, 4.5 wt % TEACSAand 0.06 wt % SLS in DI water. An Isopar G solution with TMC was alsoprepared and sonicated for 10 minutes. To this solution was added ahomogenous solution of the molecular additive dissolved in an aromaticcosolvent (xylene or mesitylene). Final concentration of the cosolventwas 4 wt % by weight and the concentration of MPD, Nanoparticle, TMC,and molecular additive are listed in the tables.

A piece of wet polysulfone support was placed flat on a clean glassplate. An acrylic frame was then placed onto the membrane surface,leaving an area for the interfacial polymerization reaction to takeplace.

Aqueous MPD solution (50 mL) prepared as described previously was pouredonto the framed membrane surface and remained for 1 min. The solutionwas drained by tilting the frame till no solution dripped from theframe.

The frame was taken off, and was left horizontally for 1 minute. Themembrane was then clamped with the glass plate in four corners. An airknife was used to finish drying the membrane surface. The membrane wasreframed using another clean and dry acrylic frame and kept horizontallyfor 1 min.

Organic solution (50 mL) was poured onto the framed membrane surface andremained for 2 min. The solution was drained by tilting the frame(vertically) till no solution dripped from the frame. The acrylic framewas removed, and the membrane was kept horizontally for 1 minute. Themembrane was then dried at 95° C. for 6 minutes.

Organic phase nanoparticles. Example 9-13, 15, 19, 22, 26-28, 35, 36,41-44, 51-56, 58, 59, 119, 121

An aqueous of MPD, 4.5 wt % TEACSA and 0.06 wt % SLS in DI water wasprepared. An Isopar G solution with TMC and nanoparticle was alsoprepared and sonicated for 30 minutes. To this solution was added ahomogenous solution of the molecular additive dissolved in an aromaticcosolvent (xylene or mesitylene). Final concentration of the cosolventwas 4 wt % by weight and the concentration of MPD, Nanoparticle, TMC,and molecular additive are listed in the tables.

A piece of wet polysulfone support was placed flat on a clean glassplate. An acrylic frame was then placed onto the membrane surface,leaving an area for the interfacial polymerization reaction to takeplace.

Aqueous MPD solution (50 mL) prepared as described previously was pouredonto the framed membrane surface and remained for 1 min. The solutionwas drained by tilting the frame till no solution dripped from theframe.

The frame was taken off, and was left horizontally for 1 minute. Themembrane was then clamped with the glass plate in four corners. An airknife was used to finish drying the membrane surface. The membrane wasreframed using another clean and dry acrylic frame and kept horizontallyfor 1 min.

Organic solution (50 mL) was poured onto the framed membrane surface andremained for 2 min. The solution was drained by tilting the frame(vertically) till no solution dripped from the frame. The acrylic framewas removed, and the membrane was kept horizontally for 1 minute. Themembrane was then dried at 95 C for 6 minutes.

Membranes without nanoparticles. Example 14, 29-34, 94-118, 120,126-136, 137-166

An aqueous solution of MPD, 4.5 wt % TEACSA and 0.06 wt % SLS in DIwater was prepared. An Isopar G solution with TMC was also prepared andsonicated for 10 minutes. To this solution was added a homogenoussolution of the molecular additive dissolved in an aromatic cosolvent(xylene or mesitylene). Final concentration of the cosolvent was 4 wt %by weight and the concentration of MPD, TMC, and molecular additive arelisted in the tables.

A piece of wet polysulfone support was placed flat on a clean glassplate. An acrylic frame was then placed onto the membrane surface,leaving an area for the interfacial polymerization reaction to takeplace.

Aqueous MPD solution (50 mL) prepared as described previously was pouredonto the framed membrane surface and remained for 1 min. The solutionwas drained by tilting the frame till no solution dripped from theframe.

The frame was taken off, and was left horizontally for 1 minute. Themembrane was then clamped with the glass plate in four corners. An airknife was used to finish drying the membrane surface. The membrane wasreframed using another clean and dry acrylic frame and kept horizontallyfor 1 min.

Organic solution (50 mL) was poured onto the framed membrane surface andremained for 2 min. The solution was drained by tilting the frame(vertically) till no solution dripped from the frame. The acrylic framewas removed, and the membrane was kept horizontally for 1 minute. Themembrane was then dried at 95° C. for 6 minutes.

The percentage of flux improvement may then calculated relative to acontrol membrane made with the same concentration of MPD and TMC, withno nanoparticles or additives, as the increase in GFD divided by the GFDof the control.

Preparation of membrane from monohydrolyzed TMC. Examples 1, 122-125

An aqueous solution of 4.0 wt % MPD, 4.5 wt % TEACSA and 0.06 wt % SLSin DI water was prepared. An Isopar G solution with 0.3 wt % TMC wasalso prepared and sonicated for 10 minutes which also containedmonohydrolyzed TMC as specified in the Tables. The Isopar solution wasallowed to sit for 1 hour before use.

A piece of wet polysulfone support was placed flat on a clean glassplate. An acrylic frame was then placed onto the membrane surface,leaving an area for the interfacial polymerization reaction to takeplace.

Aqueous MPD solution (50 mL) prepared as described previously was pouredonto the framed membrane surface and remained for 1 min. The solutionwas drained by tilting the frame till no solution dripped from theframe.

The frame was taken off, and was left horizontally for 1 minute. Themembrane was then clamped with the glass plate in four corners. An airknife was used to finish drying the membrane surface. The membrane wasreframed using another clean and dry acrylic frame and kept horizontallyfor 1 min.

Organic solution (50 mL) was poured onto the framed membrane surface andremained for 2 min. The solution was drained by tilting the frame(vertically) till no solution dripped from the frame. The acrylic framewas removed, and the membrane was kept horizontally for 1 minute. Themembrane was then dried at 95° C. for 6 minutes.

See Table X.

The invention claimed is:
 1. An interfacial polymerization process for preparing a highly permeable reverse osmosis (RO) membrane, comprising: contacting on a porous support membrane, a) a first solution containing a polyfunctional acyl halide, and b) a second solution containing a polyamine, wherein a metal beta-diketonate compound is present in a) or b) during the polymerization reaction, wherein at least one of solutions a) and b) contains nanoparticles; and recovering a highly permeable RO membrane.
 2. A RO membrane prepared according to the process of claim 1 wherein the Ro membrane is characterized by a flux that is greater than the flux of a RO membrane prepared in the absence of the metal beta-diketonate compound.
 3. The interfacial polymerization process of claim 1 in which the first solution contains a polyfunctional acyl halide and nanoparticles.
 4. An interfacial polymerization process for preparing a highly permeable reverse osmosis (RO) membrane, comprising: contacting on a porous support membrane to form a discrimination layer by interfacial polymerization: a) a first solution containing a polyfunctional acyl halide; and b) a second solution containing a polyamine and a metal additive selected from among strontium hexafluoroacetylacetonate (Sr(F₆acac)₂) and aluminum acetylacetonate (Al(acac)₃), wherein at least one of solutions a) and b) contains nanoparticles; and recovering a highly permeable RO membrane comprising the porous support membrane and the discrimination layer, wherein the RO membrane is characterized by a flux that is greater than the flux of a RO membrane prepared in the absence of the metal additive.
 5. The process of claim 4, wherein the polyamine is selected from among diaminobenzene, triaminobenzene, m-phenylene diamine, p-phenylene diamine, 3,5-diamino-benzoic acid, 2,4-diaminotoluene, 2,4-diaminoanisole, xylylene-diamine, ethylenediamine, propylenediamine, piperazine, and tris(2-diaminoethyl)amine.
 6. The process of claim 4 wherein the polyfunctional acid halide is selected from among trimesoyl chloride, trimellitic acid chloride, isophthaloyl chloride, and terephthaloyl chloride.
 7. The process of claim 4, further comprising exposing the discrimination layer to a sodium carbonate solution of pH 8-12 for a time period from about 10 seconds to about 30 minutes.
 8. The process of claim 4, further comprising applying a rinse to the discrimination layer, wherein: a) the rinse comprises water at a temperature of from 60° C. to 98° C.; or b) the rinse comprises a chlorine species.
 9. A RO membrane prepared according to the process of claim 4, wherein the membrane exhibits: a) a salt rejection of at least 99.5% when the membrane is exposed to deionized water containing 32,000 ppm NaCl at a temperature of 25° C. and at a pressure of 800 psi; or b) a flux of at least 30 gfd when the membrane is exposed to deionized water containing 32,000 ppm NaCl at a temperature of 25° C. and at a pressure of 800 psi; or c) both a) and b).
 10. A method of purifying brackish water or seawater, comprising contacting the brackish water or seawater with the RO membrane of claim
 9. 